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GEOLOGY
OF THE SOUTHERN PART OF THE
PROVINCE SANTA CLARA, CUBA

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GEOLOGY
OF THE SOUTHERN PART OF THE
PROVINCE SANTA CLARA, CUBA

PROEFSCHRIFT

TER VERKRIJGING VAN DEN GRAAD VAN
DOCTOR IN DE WIS- EN NATUURKUNDE
AAN DE RIJKS-UNIVERSITEIT TE UTRECHT,
OP GEZAG VAN DEN RECTOR MAGNIFICUS
Dr. W. E. RINGER, HOOGLEERAAR IN DE
FACULTEIT DER GENEESKUNDE, VOLGENS
BESLUIT VAN DEN SENAAT DER UNIVER-
SITEIT TEGEN DE BEDENKINGEN VAN DE
FACULTEIT DER WIS- EN NATUURKUNDE
TE VERDEDIGEN OP MAANDAG 22 FE-
BRUARI 1937, DES NAMIDDAGS TE 4 UUR

DOOR

AREND ALBERT THIADENS

GEBOREN TE UTRECHT

DEZE dissertatie VERSCHIJNT TEVENS ALS No. 12 VAN DE PHYSIOGRAPHISCH-
GEOLOGISCHE REEKS DER GEOGRAPHISCHE EN GEOLOGISCHE MEDEDEELINGEN

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''Mr,

Aan het einde van mijn studie aan de Utrechtsche Universiteit is het
voor mij de vervulhng van een lang gekoesterde wensch, dank te brengen
aan allen, die het mogelijk gemaakt hebben, dat mijn studietijd een zoo
goede is geweest.

Dat ik in de eerste plaats hier aan U denk. Hooggeleerde Rutten,
Hooggeachte Promotor, zal niemand, en zeker niet U zelf, verwonderen.
Mijn kennis van en liefde voor de geologie dank ik U. Ik reken het mij
tot een groot voorrecht in Utrecht geologie gestudeerd te hebben en dus
deel gehad te hebben aan Uw toegewijde zorg en belangstelling jegens Uw
studenten. De steeds bereidwillige hulpvaardigheid, waarmee U mij in mijn
werk terzijde hebt gestaan, heeft een onuitwischbare indruk op mij gemaakt.

In de tweede plaats geldt mijn dank U, Hooggeleerde Schmutzer,
voor de moeite, die U zich mijner getroost hebt. Bij de bewerking van
mijn proefschrift heb ik dankbaar gebruik mogen maken van Uw steeds
ter mijner beschikking gestelde petrografische kennis.

Hooggeleerde Brouwer, Oestreich, Mohr en Vening Meinesz, het
volgen van Uw colleges heeft zeer veel bijgedragen tot de verdieping van
mijn wetenschappelijke kennis.

Mijn hispanophile instelhng heeft aanzienlijk aan inhoud gewonnen
door het contact met U, Hooggeleerde van Dam.

Tenslotte ben ik dankbaar voor de vriendschap, die ik in en buiten
het Geologisch Instituut in mijn studententijd heb mogen ondervinden.

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CONTENTS.

Page

INTRODUCTION .............................. 1

Chapter I: GEOLOGICAL HISTORY....................... 5

Chapter II: STRATIGRAPHY AND PETROGRAPHY:

Schist Formation: General; age; pétrographie
description of marbles and crystalline hme-
stones, mica-schists, gneisses, chlorite-schists,
serpentine-schists, amphibohtes, actinohte-
schists, calcite-actinohte-schists............. 7

Tuff Formation: General; age; pétrographie des-
cription of porphyrites, diabases, spilites;
spilitic problem; vitric tuffs, crystal-tuffs, tuff-
porphyrite-breccias and Provincial limestones 11

Contact Tuff Formation and Diorite Intrusion 18

Serpentine................................... 21

Quartz-Diorites and other Rocks Belonging to
the Quartz-Diorite Intrusion: General and
age; pétrographie description of quartz-diorite,
gneissic diorite and gneiss, diabaslc-quartz-
diorite, hooibergitic rocks, gabbro-diorite, oli-
vine-pyroxenite, hornblendite, metahooiber-
gites, amphibolites, quartz-diorite-porphyrites,
hornblende-diorite-porphyrite, leucocratic dike
rocks, lamprophyric dike rocks, foreign in-
clusions .................................. 21

Habana Formation: General and age; structures;
petrography; facies and thickness; list of fossils 40

Tertiary: General; structures petrography; list of
fossils of Upper Eocene, Oligocene, Oligo-
Miocene age.............................. 44

Page

Chapter III: TECTONICS: discussion of the Schist Formation;

orogenetic phases..................................................48

Chapter IV: PETROLOGICAL NOTES............................................51

Chapter V: DESCRIPTION OF SURVEYED COURSES:

1.nbsp;Carretera Central from the Rio Calabazas over
Cabaiguan-Guayos-Sancti Spiritus to Jatiboniconbsp;55

2.nbsp;Baez-Fomento-Manacal-Trinidad..........................57

3.nbsp;L. 330 S.of Provincial via Manicaragua to

M. 269 S.of Manicaragua....................................58

Chapter VI: PREVIOUS LITERATURE............................................61

BIBLIOGRAPHY................................................................66

EXPLANATION TO THE PLATE..........................70

INTRODUCTION.

In this paper the geology of the Southern part of Santa Clara Province
in the middle of Cuba is treated. The district here described is bounded
on the North by a line drawn over Central Caracas, Guayos, San Juan
de los Yeros, Central Pastora, Provincial, Baez and the crossing of the
Rio Calabazas with the Carretera Central. The Northern part of Santa
Clara Province has been described by M. G. Rutten (41).

The material which forms the base of this description, has been collected
during a geological survey by students from the University of Utrecht,
Holland under the leadership of Prof. L. M. R. Rutten, with Mrs. C. J.
Rutten-Pekelharing, Miss A. Röntgen, my fellow-students L. W. J.
Vermunt, H. J. Mac Gillavry, M. G. Rutten, and the author of this
paper.

The fieldwork in Santa Clara Province has been done during the second
part of February, the whole of March and the first half of April of the year
1933 during which time both the Northern part described by M. G. Rutten
and the Southern part described in this paper have been surveyed. The
results of our researches and the notes and samples bearing on the Southern
part of Santa Clara Province have been committed to my care to compile
a geologic description.

In the field we had at our disposal the military maps of Cuba on the
scale of one inch to a mile. Already the first day these maps appeared to
be unfit for geological fieldwork and a fortiori for a base of a geological
map. Instead of using these unreliable maps we surveyed our own courses
by taking the direction with a geological hand-compass and measuring
the distance by counting our paces or by noting the speedometer of the
motor car. In Flolland we had also at our disposal the nautical charts
of the American Navy and special blueprint maps of the quot;Carretera Centralquot;,

the central highroad along the axis of the island. The construction of the
topographical map, which forms the base of our geological map has been
carried out as follows : the nautical chart gave us the location of Cienfuegos,
Casilda, the Obispo and La Isabella (on the North coast, near Sagua la
Grande). In consequence we plotted out the courses between La Isabella
and Cienfuegos, using for the Northern part of the Santa Clara Province
the map of Rutten Jr. and for the Carretera Central the blueprints. According
to our survey the distance La Isabella-Cienfuegos was 4 km. shorter than
on the nautical chart. To eliminate this difFerence it would have been best
to divide the difFerence over the whole distance La Isabella-Cienfuegos.
This was impossible, as the map of M. G. Rutten of the Northern part
of the province had already been published. Now there were two things I
could do. 1.— I could make the correction of 4 km. in my district only.
In that case the distance from coast to coast would agree with the nautical
map, but there would be striking mistakes in the map of my district, as for
instance the highroad Cienfuegos-Hormiguero, which is 16 km. long,
would be on my map 18 km. 2.— I could remove the position of Cienfuegos,
Casilda and the Obispo and with them the whole Southern coast 2 km.
to the North, and divide the other 2 km. in the traces in my district. In this
case our map would not agree with the nautical maps concerning the
distance Cie^uegos-La Isabella, but our map would become a better
representation of the surveyed roads.

I chose the last construction. Next, the courses Cienfuegos-Cumanaya-
gua-Manicaragua-Santa Clara-Carretera Central-Sancti Spiritus-Obispo and
Santa Clara-Placetas-Fomento-Manacal-Trinidad-Casilda were plotted, and
after some slight corrections, our map agreed with the nautical chart. As
can be seen from the map I had at my disposal several polygons, with the
help of which I could make further corrections. The sketch map obtained
in this way is more useful than the Cuban mihtary maps. Two maps have
been prepared : one to show the geology, and another with the quot;localitiesquot;,
where determinable rocks or fossils have been sampled. All the courses
surveyed by us, and these only are on the maps. As the map shows, the
surveyed area is by no means covered by a dense network of observations,
our survey having been only a preHminary one. Nevertheless, mostly I
filled in the geological map as, according to our conception, the structure
and geological history of our area is rather simple. Observations about
the landscape and the topography helped us, moreover, to make a geological
map covering large areas of the surveyed district. There are, however, in
the East part several quot;white patchesquot; on the map, as on these places more
than one interpretation of the data at hand was possible. Moreover, with
both maps one can differentiate immediately the quot;direct observationsquot;
and the quot;interpretationsquot;. I intended to put into the map all tectonical
observations. Only on places where many observations were made close
together, some had to be omitted for the sake of clearness and readableness.
This could easily be done as the strikes and dips in these exposures only

differ slightly from one another; so there cannot be question of alteration
of the tectonical features by subjective selection of strikes and dips on
some places.

At T. 1384 and T. 1387A Dr. Tschopp, of the Bataafsche Petroleum
Maatschappij, found Rudists, which he gave to us and which have been
described already (47).

The numbers with D quot;in parenthesesquot; indicate the number in the
thin section collection of the Mineralogical-Geological Institute of the
vState University in Utrecht.

Previous literature is treated in the last chapter. This has been done
since our survey has been the first more or less detailed one of this part of
the island. The literature is of more general character, and has not influenced
our survey to a large extent.

This paper is written in English in order to make it accessible to the
many American geologists who are studying the West Indies.

To all those who have given me help and advice I am greatly indebted
and I wish to express my sincerest thanks for it.

I tender my thanks in the first place to the quot;Molengraaff-Fondsquot;
and the quot;Bataafsche Petroleum Maatschappijquot; for their financial support
to our field work. To the quot;Bataafsche Petroleum Maatschappijquot; more-
over I am beholden for several fine fossils from Southern Santa Clara Pro-
vince.

One of the pleasantest features connected with the preparation of this
paper was the ready cooperation in the field and on the laboratory with,
my fellowtravellers. Therefore I take the opportunity afforded me on this
place to express my gratefulness to all of them. In the first place to Prof.
Dr. L. M. R. Rutten, the leader of the expedition, and Mrs. Dr. C. J.
Rutten-Pekelharing, whose experienced advices and help always were
put at our disposal. Next to Miss Agnes Röntgen my faitWul companion
on the Cuban expedition and my wife-to-be. Finally to my fellow-students
L. W. J. Vermunt, H. J. Mac Gillavry and M. G. Rutten. The pleasant
collaboration, in the joint purpose, under the leadership of Prof. Rutten,
on our expedition, and afterwards in Holland will always be a gratifying
remembrance to me.

I owe thanks to the Cuban Government and the Sociedad Geografica
de Cuba with the president Ing. Juan Manuel Planas, for the way
in which they promoted our interests before and during our sojourn in
Cuba, and I will never forget the undefatigable helpfulness and interest of
Ing. Felix Malberti. The pleasant intercourse with the kind and hospitable
culsan people has been a fine experience to me.

To Mr. Poliakof of the Compania Shell Mex. in Habana I ame
indebted for all he did for us.

At Flormiguero, our first camp on Cuba, we were greatly helped by
the hospitality of the family Ponvèrt and the assistance of the late Mr.
H. Pekelharing.

The long discussions with Dr. Tschopp on the Cuban geology during
our excursion has been of great interest to us.

To Prof. Schmutzer I am indebted for the revision of many of my
thin-sections, and moreover for his advice concerning petrographical
matters.

To Mr. W. van Tongeren I owe thanks for the analyses he made for me.

Mr. J. van Dijk prepared for publication the maps and photographs
of this paper with careful application. Mr. J. Grootveld and Mr. J. Vermeer
made the many thin sections.

Mr. ViCKERS read and revised the engHsh text of the paper.

Chapter I: GEOLOGICAL HISTORY.

The core of Southern Santa Clara Province here described consists
of Cretaceous and, very probably. Upper Jurassic rocks, bordered and
partly covered by younger Tertiary rocks belonging to the Eastern part
of the Colon basin and the Western part of the Moron basin.

Geologic history begins with the genesis of those rocks, which furnished
by metamorphism the schists and marbles of the Schist Formation. The
age of these rocks cannot be stated with certainty, as fossils, if formerly
present, entirely disappeared in consequence of the metamorphosis. By
comparison of these rocks with others, found elsewhere on Cuba and on
surrounding islands, it may be deduced that the age is very probably Lower
Cretaceous and Upper Jurassic. This age, however, has not been proved
and the rocks may be very well older. They are at least of pre-Middle Creta-
ceous age. The Schist Formation comprises many paraschists and probably
some orthoschists, all belonging to the quot;meso-zonequot;. They mainly consist
of quartz-bearing marbles and mica-schists.

The facies of the original rocks (calcareous and argillaceous) is not
known, because of to the high grade of metamorphosis. The thickness of
the complex, being about 11000 m., proves that the sedimentation of these
rocks took place in a region of strong submergence. The Schist Formation
outcrops in the Southern part of the district in two large cupola-like anti-
clines, forming the three Sierras of the Trinidad Mountains. The serpentine
schists of the Schist Formation easily may be distinguished from the
Upper Cretaceous serpentines of the large serpentine massive in the
Northern part of the Province.

The next following formation is the Middle Cretaceous Tuff Formation,
consisting of volcanics (porphyrites, diabases, spilites, glass-tuffs, crystal-
tuffs and tuff-porphyrite-breccias) and sedimentary rocks among which the
Provincial limestone with Caprinids and many other fossils. These rocks
are very probably of Cenomanian-Turonian age, and have been formed
in a sea with varying depth during a long general subsidence. The Tuff
Formation is very thick. In one section we found a thickness of 8000 m.

Following the volcanic and sedimentary deposition of the rocks of
the Tuff Formation and Provincial limestones, enormous masses of dioritic
magma intruded. Serpentine, occurring only in one small exposure, is
of minor importance. The first consolidation products of the dioritic magma
are hooibergitic rocks, which are mostly found altered by dynamo-meta-
morphism and contact-metamorphism, the latter caused by the somewhat
later consolidated quartz-dioritic rocks and the aplitic dikes. The large
bulk of the intrusive mass, which probably is a batholith, is built of quartz-
diorite with aplitic and lamprophyric dikes and some quartz-diabases.

On the Northern side of the intrusive mass quartz-diorite-prophyrites
are common and the rocks of the Tuff Formation are affected by contact
metamorpliism on many places. At the end of the intrusion, after the
consolidation of the igneous rocks and before the sedimentation of the
rocks of the Upper Cretaceous Habana Formation, orogenic forces caused
rather strong folding and faulting. Probably the schists came to the surface
during this orogenesis. The schists and diorites are separated from each
other very probably by a long straight fault. In the dioritic rocks many
inclusions of amphibolitic rocks are found, which are altered gabbros,
altered hooibergites, magmatically stooped porphyrites of the Tuff Forma-
tion and rocks of unknown origin.

After the intrusive and orogenetic activity followed a period of denuda-
tion, and then the sedimentation of the transgressive rocks of the Habana
Formation of Uppermost Cretaceous age. The rocks of this formation
contain a rich fauna of Forammfera and Rudistids and other fossils. Because
of the occurrence of species of the genus Lepidorbitoides we may parallellize
this formation with the Maastrichtian in F.urope. At the side of Orbitoidal
and Rudist limestones and marls, in this formation vitric tuffs, crystal tuffs
and many tuffaceous limestones are found, witnessing a slight volcanic
activity during its sedimentation. Porphyrites, although very probably
observed N. of Guayos (Carretera Central) have not been sampled in the
district. The rocks of the Habana Formation have been deposited in a
shallow sea. A minimum thickness found in our district is about 700 m.

After the sedimentation of the rocks of the Flabana Formation a second
orogenesis begins and a large stratigraphical gap is found between the
Maastrichtian and Upper Eocene.

The character of this second orogenesis has been stronger in the NE.
part of the district than in the SW.part.

Following the second orogenesis and a second period of denudation,
limestones and marls of Upper Eocene and Oligocene age have been formed,
lying in conformable beds. The age of these rocks is determined by many
Larger Foraminifera amongst which species of the genera Dictyoconus^
Camerina, Lepidocyclina, Helicolepidina and Discocyclina (Upper Eocene), and
the subgenus Eulepidina (Oligocene). These rocks are sHghtly folded,
indicating the existence of a third orogenesis. The age of this orogenesis
is pre-Upper Oligo-Miocene as Upper Ohgo-Miocene rocks with Miogypsina
and Amphisorus are found almost or quite horizontal.

After this third orogenesis Upper Ohgo-Miocene marls and conglo-
meratic limestones were formed, carrying species of the genera Arcbaias,
Amphisorus and Miogypsina.

West of Jatibonico these rocks are found dipping very gently over
a large distance, proving that a fourth, post Upper Ohgocene-Lower Miocene
orogenesis occurred. The complex of Tertiary strata is very thick. N. of
Trinidad e.g. about 3000 m. South from Manacal the transgressive Tertiary
beds form a 5000 m. thick complex.

Chapter II: STRATIGRAPHY AND PETROGRAPHY.

Schist Formation.

We find the Schist Formation in the Southern part of the Province
where it forms the Sierra de San Juan, Sierra de Trinidad and, very probably,
the Sierra de Sancti Spiritus. These Sierras are strongly accidentated moun-
tains, reaching an elevation of 981.5 m. in the Pico de Potrerillo.

The Schist Formation comprises the following rocks: quartz-marbles,
crystalline limestones, calcite-quartz-schists, mica-schists, quartz-mica-schists,
gneisses, quartz-chlorite-muscovite-plagioclase-schists, chlorite-schists, cal-
cite-chlorite-schists, calcite-quartz-chlorite-schists, serpentine-schists, am-
phibolites, amphibole-albite-epidote-schists, actinolite-schists, and calcite-
actinolite-schists. The large bulk of the Schist Formation is formed by
the mica-schists and marbles. This two types of rocks are rather evenly
distributed and alternate continually with one another.

In the Sierra de San Juan and the Sierra de Trinidad the rocks of this
formation form a large cupola-like anticline, as can be seen from the dips
on the map. At some localities on the uttermost North border of this cupola
we find the schists vertical and even overturned with a steep southward
inclination. In the Sierra de Sancti Spiritus the formation, very probably,
forms another dome-like anticline. We are, however, not absolutely sure
about this last mentioned cupola, as the survey in this part of the district
has been unsufficient.

As can be seen from the sections, the Schist Formation is a very thick
complex. On the North side we find a thickness of about 1 1700 m. and
on the South side of 7100 m.

All the rocks of this formation show more or less traces of cataclasis.
On some places this cataclasis has been rather strong.

The Schist Formation is bounded on the South by transgressive Tertiary,
on the East, North and partly on the West by rocks of the Dioritic Intrusion,
and on the North-West by rocks, belonging to the Tuff Formation. No
evident traces of contact metamorphism have been found, and, as the schists
are the oldest rocks of the district this probably might be an indication for
the supposed fault on the boundary between the Schist Formation and the
dioritic rocks. This will be discussed in the chapter on Tectonics.

AGE: In the geologic history we placed the Schist Formation at the
beginning. In consequence of the rather strong metamorphism, fossils, if
formerly present, have entirely disappeared. So it is impossible to state
the age with certainty. There are, however, geological evidences for our
assumed age.

The Schist Formation is pre-Tertiary as it is covered by transgressive
Tertiary beds, which contain detritical schist material.

The schists are pre-Upper Cretaceous, since we find detritical schist
material in the Maastrichtian beds.

The Schists Formation is pre-dioritic, as, in Isla de Finos (36) a
malchite intrudes clearly a formation of schists, which are in every respect
comparable with those of Santa Clara. In the Santa Clara region itself it is
difficult to find arguments, which prove the above-stated age-relation. The
occurrence of small patches of diorite within the schists area on the railroad
Fomento-Trinidad (M. 667, D. 16773, D. 16774; and M.715, D. 16782);
and the occurrence of compact pyritic ores at the Mina Carlotta (M. 254,
D. 16715) SB. of Cumanayagua within the schists seem to prove the same
age-relation. On the other hand it is striking, that no true contact-meta-
morphosis has been observed in the schists near the contact of the diorites.

The schists are very probably older than the peridotites-serpentines
of Northern Santa Clara. M. G. Rutten describes inclusions in these ser-
pentines of meso-zonatic metamorphic rocks, comprising: amphibolites
and actinolite schists and moreover glaucophane- and muscovite schists.
Of these rocks the albite-amphibolites and the actinoHte schists are highly
ahke those found in the Schist Formation and described below. This makes
it very probable, as Rutten already noticed, that those inclusions quot;have
originated from a formation in the deeper underground of the province,
which is the equivalent of the Schist Formationquot;. (41 p. 17). If this last
supposition holds true the Schist Formation is older than these serpentines.
It must be observed, however, that in the Sch. Form, no glaucophane-and
muscovite schists have been found, and only at some locahties amphibohtes,
while the marbles and mica schists and gneisses, which form the great bulk
of the Trinidad Mountains, do not occur as inclusions in the Serpentines
in Northern Santa Clara. Perhaps, here we are dealing with different facies
of the same formation.

The schists are older than the rocks of the Tuff Formation for the
following reason: the tuffs dip away from the schists, as can be seen from
the map. If the Schists are autochtonous, which is highly probable, they
must be the oldest rocks of the region, forming, a large, highly meta-
morphosed, crystalline complex.

The most important argument for our assumed age we find in the
comparison with the lower part of the San Andres Formation in mountain
ridges of Pinar del Rio. Here L. W. J. Vermunt (58) found quartzites,
marbles, crystalline limestones, phyllites etc. all of which show a great
analogy with the Trinidad schists, although they are less metamorphosed.
In the San Andres Formation Upper Jurassic Ammonites and Lower
Cretaceous Aptychi (54) have been found in concordant intercalations.
Comparing the Trinidad schists with the lower part of the San Andres
formation we presume an, at least, Upper-Jurassic age for the Schist For-
mation in Southern Santa Clara.

Pétrographie description.

Marbles and Crystalline limestones. Dark grayish-blue rocks,
cut by many white calcite veins, thin-bedded or in very thick layers. Coarse-
to medium-grained, clearly crystalline, and mostly clearly foliated. The
quartz-bearing marbles are of lighter colour than the crystalline limestones.
The former are compact crystalline with dark and light patches. Microscopi-
cally they show a coarse granoblastic structure. Large calcite crystals, often
polysynthetically twinned, contain poikilitic quartz quot;dropsquot; and, in distinct
portions, a dusty, dark powder of a black mineral which, very probably,
is graphite. In one almost black rock the graphite occurs in such a large
amount, that it could be separated and tested (M. 240, D. 16707). Sometimes
a few muscovite flakes are present. The crystalline limestones show micros-
copically a medium-grained, granoblastic structure with the following
components: inequigranular calcite, almost always with polysynthetic
twinning and also very often with compound twinning; often interlocking
grains ; a varying amount of homoeoblastic quartz grains ; always a constant
amount of small muscovite flakes, situated parallelly to the schistosity.
Accessory components are albite and orthoclase, pyrite in varying amount,
magnetite, apatite, zircon and graphite. The pyrite occurs in cubes, which
often are altered into hematite. Magnetite occurs in small and large crystalls,
often changed into limonite. Albite and orthoclase are clear.

It is difficult to state whether we have to deal with epi-meso- or kata-
marbles. The unequigranular, coarse to medium granoblastic structure and
the mineral composition probably point to the meso-zone.

Between the quartz-bearing crystalline limestones and the gneisses and
mica-schists we found transitional rocks. L. 27 (D. 17107) and V. 97 (D. 16845,
D. 16846) are fine schistose rocks with dark-blue and grayish layers some-
times micro-folded. These rocks are granoblastic, built up by quartz and
calcite in varying amount. There are layers with predominant calcite and
other ones with predominant quartz, while some layers are built up entirely
by quartz, which is fine grained and shows strong schistose structure.
Sometimes a small amount of dark pleochroitic biotite flakes mark the
microfolds. Accessorily there is always a varying amount of oxidic ore. At
M. 241 (D. 16710) a very lose foliated, gray-green coloured calcitic-mica-
schist occurs, which is composed of alternating layers of mica-schist, and
quartz-marble, and of transitional patches with medium-to coarse-grained
calcite, quartz, mica and oxidic ore with accessory titanite.

The mica-schists are white-lightgreen-gray crystalline rocks, more
or less strongly foliated. The components are quartz and colourless or green
mica and oxidic ore. The quartz shows a certain tendency to elongation
in the common direction, while the slender flakes of the mica show a clearly
parallel arrangement, and sometimes forms streaks through the rock. The
quartz is coarse-to medium-grained, only somewhat interlocking. The mica

is muscovite or biotite, the latter p.p. altered into chlorite. The oxidic ore
is magnetite with hematite. Accessory there may be some colourless garnet
and apatite.

The gneiss is whitish to grayish and rather coarse-grained. The
components are quartz, forming the large bulk, orthoclase, albite, oligoclase,
muscovite, calcite as constituents in medium amount and accessorily apatite
and oxidic ore. The structure is granoblastic, slightly interlocking. Orthoclase
contains poikilitically small fragments of the other minerals. Albite and
oligoclase are clear, the latter typically showing the plagioclase cleavage.
Quartz forms interlocking, inaequigranular grains, muscovite broken
plates.

At M. 254 we found a quartz-chlorite-muscovite-plagioclase-schist
(D. 16719). Prédominent component is quartz in medium to coarse, inter-
locking grains. Albite and orthoclase, light green fibreous and spheroidal
chlorite, muscovite, zoisite, apatite, pyrite, hematite and limonite are the
other components. This rock is a transition between gneiss and quarzite.

Chlorite-schists A. 247, (D. 17020); L. 259, (D. 16453, D. 16454);
L. 563, (D. 16599); V. 61, (D. 16821) are light-green to green, greasy, more
or less foliated rocks, weathering with a red-brown colour. Microscopically
we see a dense, scaly aggregate of chlorite with zoisite and magnetite, and
accessory calcite. The chlorite is clinochlor with refractive index of 1,59.
Zoisite forms rather large idiomorphic grains. Magnetite is granular.

At A. 297, (D. 17018, D. 17019); M. 154, (D. 16668) and M. 669 in
Manacal (D. 16775) serpentine-schists are found. The rocks are light
to dark green, compact and, in one case, foliated. Under the microscope
we see bordering against one another some patches of serpentine with
quot;Maschenstrukturquot; and many others with fibres arranged in beautiful
quot;Gitterstrukturquot;. In one thin section we found a quot;Gitterstrukturquot; with
the serpentine flakes arranged in the direction of amphibole cleavages
as can be seen on the photograph. (Plate, fig. 1). This serpentine has a
refractive index of 1,56 and a positive optical character. These rocks pro-
bably originated from an amphibole-peridotite. They are clearly different
from the serpentine from L. 117 (D. 16408) described below and the serpen-
tines from the Northern half of Santa Clara described and figured by M.
G. Rutten.

Amphibolites (L. 628, D. 16630) are light green, foliated rocks,
showing macroscopically amphibole and plagioclase grains. Microscopically
the rocks appear to be holocrystalline poikiloblastic. Components are
coarse grained plagioclase which is very clear and contains inclusions of
the other constituent minerals, amphibole: light green, not pleochroitic,
in large porphyroblastic and smaller grains, calcite, chlorite, epidote,

muscovite and titanite. The amount of epidote can become equivalent or
even larger than the amount of amphibole. Then we have epidote-amphi-
bolites.

The actinolite-schists (L.628, D. 16628, D. 16629) are of highly
schistose structure. The rocks are built up entirely by actinolite and epidote,
both of which form large elongated crystals. Finer grained actinolite schists
with a porphyroblastic structure occur also. Here actinolite forms the
porphyroblasts, laying in a nematoblastic groundmass existing of actinolite,
chlorite, magnetite and hematite.

Calcite-actinolite-schists (V. 103, D. 16847; M.258, D. 16721)
of the Trinidad mountains are green shghtly foHated rocks. Microscopically
they show a highly foliated texture, porphyroblastic with a fibroblastic
groundmass. The porphyroblasts are poikiloblastic. The components are
calcite in elongated crystals, albite and oligoclase with parallelly arranged
inclusions, long and short streaks of actinohte parallel to the common
direction or not so, rounded zoisite grains, rounded and elongated epidote
grains, pyrite and titanite.

At V. 92 (D. 16843) we found a green, grainy foliated plagioclase-epidote
-actinolite-schist which microscopically shows a highly poikiloblastic
structure. It is built up by clear albite and oligoclase grains containing
many inclusions, epidote grains and needles, some quartz, and calcite, and
much fibreous light green actinolite crystals together with muscovite and
chlorite. Oxidic ore and titanite seem to be accessory.

Almost all rocks of the Schist Formation show more or less clearly
traces of cataclasis. The calcite twins are bent or broken, the quartz shows
undulatory extinction, and, when the cataclastic action has been stronger,
we see a clear mortar structure, especially around the quartz and calcite
crystals. The structure and composition of the rocks suggest that they
belong to the mesozone, and that most of them are para-schists.

Tuff Formation.

This formation comprises both volcanic and sedimentary rocks.

The former are porphyrites, diabase-porphyrites, diabases, spihtes,
vitric tuffs, crystall tuffs and tuff-porphyrite breccias. The latter are cherts,
limestones and marls. The volcanic rocks alternate with one another, and
the limestones, which furtheron will be called the Provincial limestones,
are found clearly intercalated in the tuffs and porphyrites. On the map
these limestones got a separate colour at those places where we were certain
of their existence. One should bear in mind, however, that there are more
Provincial limestones in the district.

The rocks of the Tuff Formation are found mainly in a broad uninter-
rupted zone running WNW-ESE along the Northern side of our district.

Here they dip monoclinally to the North and, as in the Northern half of
Santa Clara Province we find the adjacent rocks of the same formation
dipping to the South, we roughly can speak of a large synclinal in the central
part of the island. As we can see from the schematic sections annexed to
this paper and from those of M. G. Rutten this formation may have a
thickness of about 8000 m.

To the East the direction of the strike changes clearly, bending from
ESE-WNW to ENE-WSW.

In the broad synclinal the Provincial limestones form a rather distinct
zone near the Northern border of the map. They form steep mountains
100—200 m higher than the surrounding hilly plain. Near Provincial the
Provincial limestones are found clearly intercalated in the tuffs, cherts and
porphyrites, several times alternating with them.

The rocks of the Tuff Formation outcrop moreover South of the
above mentioned synclinal zone, at places where the Upper Cretaceous
and/or the Tertiary transgressions do not cover them as e.g. N., NE. and
E. from Sancti Spiritus and E. and S. from Soledad. West of Cabaiguan
the Tuff Formation outcrops in the core of an anticline of the Upper Creta-
ceous beds.

Age. The age of this formation is very probably Cenomanian-Turonian,
as the fauna of Caprinids occurring in the conformably interbedded Provin-
cial limestones can be parallellized with Cenomanian-Turonian faunas in
Mexico, namely with the faunas at Soyatlan de Adentro (Jalisco) and of
the Escamela Limestones (Orizaba) described by R. H. Palmer (30).
I studied the Cuban fauna and published the results of this study separately
(48). The age of the Mexican faunas is discussed in this study, and I
concluded that we can be pretty sure that the Cenomanian-Turonian age,
stated by R. H. Palmer and others is right. So we accept this age for the
Provincial limestones too. This agrees rather well with the Turonian-Emscher
age assumed by M. G. Rutten for the uppermost beds of his Tuff Series,
on the base of Ammonites studied by Jaworski. In the Southern part of
the Province the limestones with these Ammonites have not been found
by us, probably, because the uppermost beds of the Tuff Formation are
not exhibited in this area.

The contact phenomena in the Tuff Series near the contact with the
diorites prove that the Tuff Formation is older than the diorites. These
contact phenomena is treated at page 18—21.

Pétrographie deseription.

The porphyrites are dark-green to dark-gray, fine-grained, hard,
rather fresh rocks with clearly porphyritic texture, the phenocrysts being
light green. Sometimes the rocks are amygdaloidal. On weathered surfaces
they are yellow to brown. The porphyrites are often found as large blocks

of several cubic metres. In the neighbourhood of bedded tuffs or cherts
they occur in concordant beds.

Microscopically we see a well established porphyritic texture. In some
rocks the amount of the groundmass is larger than that of the phenocrysts ;
in other rocks they are about equivalent. The phenocrysts are plagioclase
and monoclinal pyroxene, the former prevailing above the latter. The
plagioclase is mostly found in groups of several phenocrysts; they are
drifted together and grown together. The average composition of the
unaltered plagioclase ranges from andesine-labradorite to bytownite. The
phenocrysts are tabular and show lamellar and intersecting twins. Often
albitisation is found, beginning along fissures. The monoclinal pyroxene
is a colourless diopsidic augite. It occurs in large, idiomorphic phenocrysts,
which are sometimes twinned, and sometimes in smaller grains too, gradually
diminishing in diameter, and passing into the augite microlites of the
groundmass. In one slide yellowish-green amphibole has been found in
large phenocrysts (V. 40, D. 16812, D. 16813). Large magnetite grains
always are present. Apatite in large crystals has been found as an accessory
mineral. The groundmass is holocrystalline, built up by small plagioclase
prisms, sometimes more or less fluidally arranged, tending to a trachytic
texture; moreover of augite grains, magnetite and chlorite between the
plagioclase laths. The composition of the plagioclase of the groundmass
sometimes could be classified as andesine-labradorite. The amount of
plagioclase and augite in the groundmass of fresh rocks is about equal.
Chlorite is an alteration product of both, plagioclase and augite. The amount
of magnetite varies strongly. In some cases it predominates above the other
components and then the rock is almost black. In other cases it occurs in
a small amount only and we have light coloured porphyrites. The felspars
decompose by weathering into chloritc and calcite, zeolites or zoisite.
Sometimes the decomposed felspars are surrounded by an ore rim. Augite
is altered into uralite and epidote or calcite ; in the groundmass into chloritc
too. Silicification is found sometimes, resulting in the occurrence of secon-
dary quartz throughout the groundmass. The amygdales are filled in with
calcite, quartz, spheroidal prehnite or spheroidal chlorite.

The diabases are dark-green, medium-to coarse-grained, crystalline
rocks. Mostly the rocks are fresh. On weathered surfaces they are brown.
Pillow structure has been found once. Microscopically the texture is more
or less porphyritic; transtional diabase-porphyrites between coarse-grained
porphyrites and normal diabases are met with. In the diabase-porphyrites
the amount of phenocrysts predominates largely above the groundmass.
Ophitic or subophitic texture always is present. The main constituent
minerals arc pyroxene and plagioclase. The plagioclase is developed in
large, tabular, twinned crystals, which mosdy arc dear or have zonally
arranged inclusions of dust. Albitization, as in the porphyrites, often is met
with. Pyroxene occurs in large and smaller crystals. It is colourless to light-

green, diopsidic augite, showing beautiful cleavage and twins. Seldom
the augite is found in idiomorphic crystals, mostly in allotriomorphic ones.
In one sample olivine has been found in large crystals, which are decomposed
by serpentinisation. The olivine is colourless to salmon coloured, pleochroi-
tic. In this case we have an olivine diabase. Magnetite forms many
large grains, apatite long needles. Occasionally quartz is found in a small
amount. It seems to be primary and occurs interstitially. Mostly the plagio-
clases are idiomorphic with regard to the quartz, sometimes the borders
show an irregular granophyric intergrowth (L. 189, D. 16434, a.o.).

By weathering, the plagioclases decompose into sericite and dust,
chlorite, epidote and calcite. Occasionally they show zonal decomposing
e.g. chlorite zones or cores are met with. Augite is altered into uralite, which
in some cases is found as a rim around the augite crystalls, or into chlorite
and calcite.

Spilites: Many more or less porphyritic rocks, composed of acid
plagioclase, augite, and magnetite with their decomposition products, I
reckon to the spilites for several reasons. 1. For their mineral composition.
2. For their texture. Rosenbusch (35, p. 449) describes the spilitesas fol-
lows: quot;Spilite (Al. Brongniart) sind Einsprenghngsfreie oder doch sehr
Einsprenglingsarme, sehr feinkörnige bis dichte, grünliche bis graugrün-
liche Ergussgesteine, die zu den Effusivformen der Gabbromagmen gehören
und sich durch grosse Neigung zur Mandelsteintextur, meist dünnplattige
oder kuglige Absonderung und leichte Verwitterbarkeit auszeichnenquot;.
Holmes (22, p. 215) gives the following definition: quot;Spihte: A basaltic
rock, generally vesicular or amygdaloidal, whose felspars have been albitized.
Pyroxene or amphibole, more or less altered, and sometimes serpentinized
olivine may be presentquot;. I used the term spilite for diabasic or basaltic
rocks with a fine intersertal structure, composed of acid plagioclases,
especially albite, augite and their decomposition products, among which
chlorite predominates. Often the rocks are weathered. Amygdales are
met with.

In Santa Clara province rocks of this type occur together with porphyrite
and diabase. The essential differences with these two mentioned rocks are
the average composition of the plagioclases and the texture. Even in the
porphyritic spilites the groundmass shows a more or less intersertal texture.
However, texturally spoken, we find all transitions between true spilites,
diabase-porphyrites, and porphyrites.

The spilites are darkgreen, compact, dense rocks, weathering with a
yellow brown colour. Microscopical study reveals holocrystalline rocks with
intersertal texture formed by divergent laths of felspar, with in the spaces
between these augite with chlorite or with other secundary minerals, which
probably originated partly from some glassy mesostasis, and magnetite. The
amount of felspar is larger than the amount of augite. The felspars are
cloudy, filled up with minute dusty inclusions. The composition ranges

from albite to oligloclase and sometimes andesine. Often they are twinned.
The augite forms small grains like magnetite. If the rock is porphyritic,
there are phenocrysts of albite-oligoclase to andesine, and of augite. The
felspars are tabular, twinned, dusty, and decomposing into chlorite,
sericite, epidote or prehnite. The augite occurs in large, allotriomorphic
grains, decomposing into amphibole. Both, augite and amphibole decompose
into chlorite and epidote. If the augite grains are large and dissected by
felspar laths we have ophitic texture.

The amygdales are filled with calcite or interlocking undulose quartz
and epidote, or spheroidal quartz. Often the spilites are silicified. The
clearly secondary quartz penetrates the intersertal spaces. The mafic compo-
nents are chloritised and the chlorite also is replaced by quartz.

The genesis of the spilites is problematic. In the literature on the spilites
the central problem is whether the origin of the albite in the spilitic rocks
is magmatic or metasomatic (either autometamorphic or exomorphic).
James Gilluly (19, p. 225) gives an extensive discussion of the question
and comes to the following results: quot;spilitic rocks are derivates of normal

alkalicalcic magmas; spilites.....have been metasomatically enriched in

albite; the enrichment was probably entirely subsequent to their consolida-
tion and brought about either by resurgent water from the wet sediments
as suggested by Daly, or by albitic solutions derived by deeper seated
différenciation along trondjemitic linesquot;. With regard to these conclusions
the following must be stated about the spilites of Santa Clara Province. As
we find them associated with marine limestones and marls, we can be pretty
sure about their submarine genesis. The associated diabases and porphyrites
sometimes show the beginning of albitization and, on the other hand, in
the spilites relics of calcic plagioclases occasionnally are met with. This
makes it probable that all albite in our spilites is of metasomatic origin. The
occurrence of the association of spilite with normal fine-grained Cabases,
and diabase-porphyrites can be more easily explained by metasomatic origin
of the albite in the spilite than by magmatic genesis of the spilites. The
albitization-process probably was limited to special places under special
conditions, as the spilites are found only very locally on several places.
Difficult to understand are the many twins in the albite crystals. Never
albitic veinlets have been found, only a quartz vein. The conditions which
caused the albitization of the spilites in our district arc unknown to me.
Concluding I can say, that for the Cuban spilites the metasomatic origin
of the albite is probable. It cannot be stated whether it was autometamorphic
or exomorphic.

The vitric tuffs are darkgreen rocks with a dense, sometimes dys-
crystalline structure weathering with a brownish colour. Microscopically
they consist of lightbrown glass, sometimes dusty and clouded by small
patches of chlorite or slightly larger ones of limonite. The refractive index
mostly is lower than 1,54. When the glass is dusty, it is difficult to measure

its refractive index. Once we found a refractive index slightly higher than
that of the canada balsam. In some cases the vitric tuffs contain no crystal
fragments at all. Mostly, however, we find angular fragments of plagioclases,
ranging from very few, diminutive fragments to a larger amount of coarser
ones. Often Radiolaria are found, at H. 41 (D. 16899) a very rich fauna
occurs of very small and larger forms, amongst which the largest ones are
spherical, measuring up to 250 /x in diameter.

Crystal tuffs and tuff-porphyrite breccias. The tuffs range
from very fine cryptocrystalline and microcrystalline tuffs to coarser crystal-
tuffs, which in their turn gradually pass into very coarse tuff-porphyrite-
breccias. The crypto-and microcrystalline tuffs and cherts are finally bedded;
the coarser tuffs and the porphyrite-breccias are poorly bedded; the coarsest
breccias are structureless. The fine-grained tuffs often show spheroidal
parting. Bloctuffs with many diaclases are found many times. The fine-
bedded tuffs alternate with the coarse tuffs. The colour mainly is green to
grayish-green, while also blue, red, and sandy-yellow tuffs are met with.
Very often the tuffs are strongly decomposed by weathering, becoming
brownish.

Microscopically they show strong variation with regard to the structure
and the composition. Both, number and dimensions of crystal fragments
increase with the decrease of the amount of the groundmass. The coarse
tuffs of pyroclastic genesis are built up almost entirely by crystal- and rock-
fragments ; the fragments being cemented by secondary minerals as quartz,
limonite, sericite and chlorite. Moreover there are tuff-porphyrite-breccias
cemented by calcite.

The dense cryptocrystalline tuffs appear to consist of a fine volcanic
dust with very few diminutive crystalfragments of plagioclase.

The microscrystal-tuffs and the coarser crystal-tuffs show a very fine-
grained quot;groundmassquot; of plagioclase, chlorite, limonite and leucoxene,
which is in some cases more or less silicified, and the fine-grained rock
becomes cherty. At the side of this quot;groundmassquot; occur larger crystal
fragments, especially of andesine and other plagioclases, some secondary
amphiboles, and chlorite and limonite as rests of former mafic constituents.
In the tuffs we often found Radiolaria. Once we found opal.

The tuff-porphyrite-breccias are built up by many large fragments of
crystals and rocks. We find, albite, andesine, labradorite and bytownite, the
last two of which being clear, twinned, and with zonal structure; andesine
rather dusty. Besides the plagioclase frequent augite, and rare olivine, light
green pleochroitic amphibole and magnetite occur. The imbedded rock-
fragments mainly can be recognized as debris of porphyrite, spilite, diabase
and vitric tuff. Porphyrites with pilotaxitic or hyalopilidc groundmass
occur.

The tuffs, and especially the coarser tuff-porphyrite-breccias are very
strongly decomposed by weathering. Calcite, epidote, chlorite or sericite

are developed from the felspars; while pyroxenes are altered into uralitic
amphibole, chlorite, and calcite. The porphyrite-fragments are altered in
many ways. The groundmass may be replaced entirely by light green chlorite
and dark brown ore, or by calcite. The phenocrysts are altered in the same
way as the crystalfragments. Apart of these strongly altered porphyrite
fragments we found also almost entirely fresh ones. This rather strong
differrence in the decomposition of the rock fragments in one sample is a
remarkable fact.

The Provincial limestones are found at many localities in the
Tuff-Formation, forming steep pronounced hills. In the Northern zone
of exposures of these limestones many Caprinids have been found. At
L. 328 Caprinids-bearing Provincial limestone was exposed imbedded
between tuff layers. At A. 236 the limestones rich in Caprinids are found
as isolated blocks in the field.

The Provincial limestones are light-yellow, dark-gray, grayishblue,
fine-to medium-grained, mostly microconglomeratic rocks, cut by many
small and larger, white calcite veins. They may be thickbedded (up to 1 m.),
but mostly they are thinbedded. These conglomeratic limestones appear
under the microscope to be built up by many small and larger rounded
rockfragments which are wholly calcified. The texture of the original
rock often can be recognized as a porphyritic one. Oolites of calcite occur
also. These rounded calcified rockfragments and oolites are cemented by
fine- to medium-grained calcite. Often the limestone contains unaltered
fragments of porphyrite, or their plagioclase phenocrysts. The latter are
of basic composition, clear, tabular, twinned, sometimes showing the
beginning of calcification. Small and larger clear quartz-grains also have
been found. In one sample in a quartz crystal a liquid inclusion was found.
As the diorite intrusion undoubtedly is younger than the Tuff Formation,
it is very probable that the quartz inclusions in the Provincial limestone
derive from some yet unknown prae-Cenomanian volcanic rock, contai-
ning clear quartz, or partly possibly from the quartz-bearing rocks of
the Schist Formation. The fact that in the tuff-porphyrite-breccias and
the crystal tuffs never quartz has been found probably can be explained as
follows: the tuffs and tuff-porphyrite-breccias are quickly sedimentated
rocks while the sedimentation of the limestones took a much longer time;
so the chance to find detritus of foreign rocks in the limestones is larger
than in the tuffs and breccias. Apart from the conglomeratic limestones,
compact, fine-grained, light yellow limestones have been found, and fine-
bedded, dark, compact marls containing many Smaller Foraminifera, partly
related to the Glohigerinidae, and dense, light-yellow, finely bedded radio-
larian limestones.

Fauna. The Provincial hmestones contain a rather rich fauna. Radio-
laria, Smaller Foraminifera, Corals and Bivalves {Caprinidae) and Nerineidae
are found. Where Radiolaria occur, their silica is replaced totally by calcite.

They are more common than the Globigerinidae, which are only found in
some places.

In the layers, where Mollusca have been found, they occur rather
abundant. They always are found in solid rock, and on weathered surfaces
in the conglomeratic limestones. They do not occur in the finer-bedded
limestones. Caprinuloidea perfect a Palmer, and Sabinia sp. were found in dark-
grayish-blue, compact, microconglomeratic limestones; Coalcomana ramosa
(G. Boehm) and Tepejacia corrugata Palmer in a light-yellow, coarser conglo-
meratic limestone. Together with the Caprinids many Nerineidae and Corals
and Smaller Foraminifera have been found, which not yet have been studied.
The occurrence of Caprinids and Corals in a conglomeratic limestone
indicates a littoral facies. The fine grained limestone with Globigerinidae and
Radiolaria inform us, however, that probably sometimes the sedimentation
took place at a longer distance of the coast.

Comact Tuff Formation and Dioritic Intrusion.

As already mentioned the diorite is younger than the Tuff Formation.
This is proved by several phenomena.

1.nbsp;Dioritic dikes in the Tuff Formation near the contact.

2.nbsp;Inclusions of altered rocks from the Tuff Formation in diorite.

3.nbsp;Contact metamorphosis in the rocks of the Tuff Formation caused by
the Dioritic Intrusion.

4.nbsp;The existence of a quot;marginal faciesquot; in the diorite at the contact with
the Tuff Formation.

ad On several places there occur dioritic dikes in the Tuff Formation
as can be seen on the map. These, however, are not always convincing, as
the exposures are often bad and the determination of the dioritic character
of the rocks was only sure in a few cases. At L. 318 (D. 16512), S. of Pro-
vincial a real quartz-diorite-porphyrite was found, at L. 320 (D. 16516) a
silicified porphyritic rock with rests of quartz-phenocrysts. At H. 255
(D. 16911), N. ofGavilan a porphyrite occurs which is rather weathered.
The groundmass is granular, composed of plagioclase tablets, primary
and secondary quartz, and chlorite. There are large and small, very dusty,
tabular plagioclase phenocrysts of medium average composition in a large
amount, and chlorite and epidote replacing the very few mafic phenocrysts.
The form of the latter sometimes suggests decomposed amphiboles. Mag-
netite in large crystals occurs. This porphyrite differs from the common
porphyrites of the Tuff Formation by a. the lack of ore in the groundmass,
b. the structure of the groundmass never containing plagioclase laths with
intersertal mafic minerals, c. the small amount of the latter or their decom-
position products both in the groundmass and the phenocrysts, d. the lack
of augite or traces of it ,and e. the composition of the plagioclase phenocrysts.
The form of the decomposed mafic phenocrysts suggests a diorite-porphyritic

origin of the rock, although the groundmass is aberrant from the common
type of diorite-porphyrites.

ad 2. In the Diorite Intrusion North of Manicaragua and La Moza
we found foreign inclusions of uralite porphyrites and uralite diabases
A. 203 (D. 17024, D. 17025); A. 306 (D. 17029); L. 334 (D. 16537); L. 337
(D. 16540); L. 338 (D. 16541); L. 339 (D. 16543, D. 16544, D. 16545);
M. 314 (D. 16739) ; M. 318 (D. 16745); M. 135 (D. 16666) ; L. 340 (D. 16546).
The last two samples are uralite diabases.

These rocks are totally uralitized and often largely silicified. The rocks
are green, fine-grained, rather hard. The porphyridc structure is visible
in several cases. Under the microscope the rocks appear to be holocrystalline,
hyp-idiomorphic porphyrites and diabases. According to the varying richness
in pyroxene of the original rocks we find uralite-porphyrite and -diabase
with a varying amount of uralite. Sometimes the rocks exist almost entirely
of this mineral. The phenocrysts of augite are endrely amphibolized and
mostly have disappeared or they recrystallized into innumeral fine, green,
pleochroidc needles and fibres of uralite and small magnedte grains.
Here and there the original pyroxene form is preserved, and we see traces
of beginning uralitizadon. The felspar phenocrysts are more or less silicified.
In the samples, where no silicificadon occurs, the plagioclases are dusty,
often twinned, decomposing into chlorite or sericite. The average compo-
sition ranges from andesine to labradorite. The groundmass is composed
by uralite, felspar, ore, epidote and chlorite and rather often secondary
quartz. Light green, slightly pleochroitic uralite occurs in broom-like
bundles, arranged in all directions, sometimes radiating, stretching beyond
the original form and space of the augite, intruding the surrounding pla-
gioclase laths. The felspar laths are dusty, partly of wholly replaced by
quartz. The quartz penetrates the whole groundmass with small irregular
grains. A rather large amount of magnetite grains is always found.

At M. 322 (D. 16751 ) near the Rio Arimao, North of Manicaragua we
we found as foreign inclusion in the diorite an uralite-zeolites rock. The
internal structure suggests very probably its diabasc-porphyntic origin.
The rock is medium-grained, porphyroblastic, built of uralite and zeolites
and relics of very dusty plagioclase. The uralite mostly is pseudomorphic
after augite, and occurs also in an irregular crowd of small, green pleochroitic
needles. The zeolites are tabular, grainy, with two directions of perfect
cleavage, irregularly twinned, with undulatory extinction, cloudy low pola-
risation colour, slightly higher than quartz, positive optical character,
negative elongation, and a refraction index only slightly lower than the
canada-balsam.

ad 3. Contact metamorphic rocks are vcry well exposed at M. 582
and M. 583 (D. 16752—D. 16760) on the Carretera Central, East of Sancti
Spintus and at A. 433 (D. 17052) North-East of Sancti Spiritus, at M. 119
(D. 16662) East of Soledad, and V. 90 (D. 16842) North of Cumanayagua.
At M. 582 and M. 583 we found the finest example of contact metamorphism.

The tuffs of the Tuff-Formation are urahtized, epidotized and sihcified. The
impure Hmestones are strongly altered. The most common product of
metamorphism in them is quot;common garnetquot;, which is colourless or slightly
yeüow. It is present in abundance in some samples, forming compact garnet
rocks. Large crystals are found which mostly are amazingly pure. Their
section is hexagonal and octogonal. The refractive index is higher than
1,77. They show distinct zones of growth, are isotropic or often biréfringent,
this property varying in successive zones. The core of the larger crystals is
anomalously biréfringent, and does not show a special growth pattern. The
large crystals are broken, and secondary clear quartz penetrated between the
garnet and in the fissures through the broken crystals. In one case the
garnet was associated with large magnetite crystals, which decomposed
into hematite. In garnet-rocks, almost entirely consisting of fine dusty
calcite and very little garnet it is difficult to state whether the calcite is
primary or secondary. In one sample a garnet rock with many calcite veins
and veinlets has been found. Here the secondary character of the calcite
is evident. One very pure limestone has been altered into coarse-grained
marble, consisting almost entirely of large, very clear, twinned calcite
crystals, cut by some small veins carrying quartz and garnet, and other
ones, carrying zoisite and chlorite or quartz and epidote.

At M. 119 (D. 16662) a garnet-wollastonite rock has been found.
This rock is very homogeneous, fine-to medium-grained, light coloured.
The garnet is regularly crowded, consisting of medium sized colourless
grains. The garnet is isotropic or biréfringent. Allotriomorphic, fine grains
of wollastonite fill in the space between the garnet. The rock is cut by small
calcite veinlets. No rests of original carbonates have been found. This rock
probably has originated from a homogeneous, rather pure lime-marl as
found in the Provincial limestones.

At V. 90 (D. 16842) we found a contact metamorphic rock of quite
another type, for here a large amount of the original carbonate has been
left. The irregular distribution of the components of the rock suggests its
conglomeratic origin. The rock is coarse-grained with poikilitic texture.
It is built up by calcite, which is recristallized in large twinned crystals,
including many small and larger grains of garnet, epidote, and chlorite.
Other patches of the rock are built up entirely by garnet and again others
by epidote and quartz. The quartz is very clear, allotriomorphic, anomalous,
showing a slightly biaxial interference figure. Probably it has come into
the rock in a later, cooler stade of the metamorphism. The garnet is isotropic
or biréfringent. Many very small and larger, colourless, idiomorphic crystals
are irregularly distributed in the rock. Slightly pleochroitic epidote forms
well-established grains. The chlorite is allotriomorphic in nests and veinlets.
Many larger and smaller garnet crystals are broken. It is possible that in the
second phase, when the quartz intruded, the garnet has been broken.

At A. 433 coarse grained marble, partly altered by contact metamor-
phism, has been found. The large calcite crystals are strongly corroded at

the border by quartz, epidote and zoisite. Locally the calcite carries also a
crowd of inclusions of these minerals. Some garnet grains occur too.

At the side of all these more or less strongly contact metamorphic
rocks there are found on several other places near the diorite intrusion in
the Tuff Formation rocks with slight metamorphism or only with tracés
of its beginning. The first effect always found is the uralitization of the
pyroxene in the groundmass and the phenocrysts of the porphyrites. In
the tuffs uralite and also quartz, and in the amygdaloidal spaces clear quartz
including fine uralite needles can be considered as traces of slight contact
metamorphism.

The silicification of the rocks of the Tuff Formation probably also is
connected with the metamorphic action of the Diorite Intrusion. On some
courses, which cross the contact of the Tuff Formation and the diorites,
no traces of contact have been found. This, however, is not astonis-
hing as often the rocks of both formations are strongly weathered, and the
contact is not exposed. In these cases we often were able to draw the boun-
dary between the two formations as the weathered diorite is easily recog-
nizable, by its typical yellowish sandy decomposition.

ad. 4. Near the contact of the diorites with the Tuff Formation we
find many quartz-diorite-porphyrites.

Serpentines.

In our district we found two distinct types of serpentine. In the Schist
Formation we found serpentine schists, which have been already described
in the petrography of the Schists on page 10.

At L. 117 (D. 16408) serpentine is found which is not foliated, and
does not show a schistose texture under the microscope. This serpentine
is very alike those which outcrop in a large area in the Northern half of
Santa Clara Province and which have been extensively described by M. G.
Rutten. The rock is light green, compact, with large discernable grains
which appear to be bastite. The rock is full of small calcite veinlets, and
broader ore-bearing calcite veins. Microscopically the rock appears to
consist of colourless or light green, leaf-like antigorite, irregularly arranged,
and of large bastite crystals, sometimes showing the pyroxene cleavage;
small and large chlorite aggregates, which are colourless and under crossed
niçois show an anomalous dark blue polarisation colour. Many large irregu-
larly arranged calcite veins with or without magnetite in medium or fine
grains and hematite are present. The original rock, which yielded this
serpentine, probably was built up mainly by rhombic pyroxene and ohvine.

Quartz-Diorites and other rocks belonging to
the Quartz-Diorite Intrusion.

Large masses of rocks of the quartz-dioritic and dioritic clans outcrop
North, East and West of the Schist Formation. As can be taken from the

map the diorite outcrop North and East of the Schist Formation has an
enormous extent. The elongation is, generally, parallel to the tectonic axes
of the mountain range. Many of the rocks belonging to the Dioritic Intrusion
are more or less strongly cataclastic, a fact which proves that after consoli-
dation the rocks were subdued to strong stresses, probably caused by
orogenic action. The time of intrusion partly coincided with a period of
mountain building. The form of the boundary between the Dioritic Intrusion
and the Tuff Formation proves a cross-cutting relation between them.
Nothing is known of the floor and the walls of the intrusive body. The
several inclusions found in the dioritic rocks probably are rests of the roof
of country rocks, which has been replaced by the intrusion. The present
author is inclined, for the above mentioned facts, especially the large extent
and the lack of knowledge about the floor, to call the large intrusive dioritic
mass a batholith. As will be seen later-on we then are dealing with a differen-
tiated batholith, mainly existing of rocks of the quartz-dioritic clan. On the
West border of the Schist Formation smaller intrusive masses are found,
which probably must be called stocks.

The way in which the Dioritic Intrusion surrounds the Schist Formation
is very peculiar. The rocks of the Schist Formation form a autochthonous
complex or are part of an overthrust mass. These two cases will be discussed
in the chapter on Tectonics. As will be pointed out there, the first possibility
is the most probable one. As the Schist Formation is older than the Dioritic
Intrusion (see below) traces of contact metamorphism in the schists caused
by the diorites probably could be expected, as e.g. replacement of the folia-
tion by the hornfels class of structure and replacement of the stressminerals
as chlorite, muscovite and actinolite by antistress-minerals. This we never
found. This fact, together with the vertical and overturned position of the
schists on the North side of the complex, and the strong cataclastic structure
found in the dioritic rocks and sometimes in the schists too, were the reasons
why we drew the boundary between the two formations as a fault.

The age of the intrusion is Upper Cretaceous. The diorites are younger
than the Cenomanian-Turonian rocks of the Tuff Formation, since the
latter are contact metamorphically altered by the former. On the other hand
the diorites are older than the Maastrichtian as in the rocks of the Flabana
Formation detritical material of dioritic rocks is found.

The Dioritic Intrusion is differentiated. The following rocks have been
found: quartz-diorite, quartz-free-hooibergite and pyroxene-hooibergite,
metahooibergite, gabbro-diorite, pyroxenite, hornblendite, amphibolites,
quartz-diorite-porphyrite, vintlite, aplites, lamprophyres, and quartz-
epidote-rocks. A rather regular distribution of the rocks is found. The
quartz-diorites and sandy decomposed diorites are found almost in the
whole area. In the centre these are the only occurring rocks. The hooi-
bergitic rocks, the gabbros, hornblendite, pyroxenite and the amphi-
bolites outcrop only on the Southern side of the batholith. When we
approach the schists, the amount of these basic igneous rocks increases.

They are strongly cut by aplitic dikes. With the exception of two samples
all the aplites found by us in the district are associated with the above
mentioned amphibole-rich rocks. On the other hand the quartz-diorite-
porphyrites are found only near the Northern border of the intrusion.
On some places they are found as dikes in the Tuff Formation. The hooi-
bergitic rocks are probably early consolidation products in the roof and the
uppermost margins of the batholithic chamber. Together with the hooi-
bergidc rocks amphibolites, which are probably magmatically stooped
country-rocks, are found. These facts suggest that we are dealing in the area
where the hooibergidc and amphibolitic rocks are found with exposures
very close to the roof of the intrusion. The many quartz-diorite-porphyrites
on the Northern border of the intrusion, represent another marginal facies
of the intrusion.

Many rocks of the dioridc intrusion are more or less strongly affected
by cataclasis. Mylonitizadon is often found. On the other hand nearby the
regions of cataclasis we find regions where no cataclasdc action has taken
place. Once undoubtedly traces of protoclasis have been found.

In the strongly cataclasdc dioridc rocks and the amphibolites often
quot;strike and dipquot; could be measured and accordingly have been drawn in
the map. The main trend of these schistose rocks indicate that the direc-
tion of the cataclastic forces had been SSW. to NNE.

Quartz-Diorites. The quartz-diorites are medium-to coarse-grained
rocks with evenly spread white and dark minerals. The white minerale are
felspar and quartz, the dark ones amphiboles, forming large columnar
crystals, measuring up to 7 mm. Nearly always the rocks are decomposed
into a yellowish, loose diorite-sand, causing a very typical landscape, as
erosion and denudation act very quickly on it, forming deep gullies. On
about only 20 localides dioridc rocks, which arc slightly or not at all decom-
posed by weathering, have been sampled.

The texture is holocrystalline and hypidiomorphic-granulose, sometimes
porphyridc, gradually passing into diorite-porphyrite and vintlite. Depending
on the presence or absence of biotite we are dealing with quartz-biotite-
amphibole-diorite or quartz-amphibole-diorite. The main constituent mine-
rals are plagioclase, amphibole, quartz and biotite. In general the plagio-
clases are the most important minerals. In some rocks, however, the amphi-
boles are prevailing. When biodte is present, it is almost equivalent with
the amphibole or the amount of biodte is slighdy smaller.

The plagioclases are idiomorphic or hypidiomorphic, large tabular or
smaller, lath-shaped in section. The composition varies from oligoclase to
labradorite. Mostly a medium composition of andesine-labradorite is found.
Simple and polysynthetic twinning is always present, while zonal crystals
often are found. The peripheric zones are more acid than the core. In one
sample vermicular quartz was found in plagioclase, probably as a result
of corrosion of the liquid containing residual quartz. Granophyric inter-

growth in a few cases is found. Albite is always present in large crystals,
filling together with quartz the room between the other minerals. Often
a very pecuhar texture is formed then: large allotriomorphic very clear
albite encloses smaller tabular dusty andesine crystals and small typically
idiomorphic, well-cleaved amphibole crystals. This texture, which seems
to be rather uncommon in the diorites, has been found several times in
Southern Santa Clara. Besides, we find albite as zonal rim around a centre
of more basic plagioclases. Mostly the plagioclases are clear. Sometimes
they are more or less strongly weathered. Once a sample has been found
with clear plagioclases containing a crowd of small and large slender plates
of sericite and grains of calcite. Usually, if weathering, the plagioclase
becomes dusty, containing fine epidote, sericite or chlorite. Orthodase is
of httle importance, clear, allotriomorphic, younger than the plagioclase.

Amphibole of both the quartz-amphibole-diorite and quartz-amphibole-
biotite-diorite is alike. The crystals are evenly distributed in the rock or
they occur in groups together. The form is varying, idiomorphic or hypidio-
morphic. Sometimes the border between amphibole and plagioclase is
irregular. Mostly the amphiboles are idiomorphic with regard to the plagio-
clase, but contain on the other side idiomorphic plagioclase inclùsions. The
amphiboles form short or long prismatic crystals, often twinned, showing
a well developed cleavage. The colour, pleochroism and extinction point
to the common green amphibole. We find at the side of the large amphiboles
small, idiomorphic ones. The amphiboles are generally clear and fresh;
only sometimes they have been partly replaced by epidote or chlorite.
Rarely in some amphibole crystals small rounded, and irregularly shaped
quartz inclusions have been found in a rather large quantity, e.g. in L. 261,
(D. 16460). This poikihtic amphibole is found in the diorite, which is very
poor in quartz. It is probably that this phenomenon can be explained by
corrosion of the amphibole by a residual liquid.

Biotite, when found, forms large broad tabular prisms and smaller
flakes. It is green to dark green or brown to black pleochroitic. Very often
it is more or less altered into light-green to green pleochroitic chlorite,
which has a typical brownish polarisation colour. In some rocks all the
biotite is replaced, and only the chlorite, pseudomorphic after biotite, is
present. Together with chlorite, epidote sometimes also replaces biotite.
Often the biotite is found in the neighbourhood of amphibole, the latter
being idiomorphic with regard to the former. Sometimes small plagioclases
are enclosed in the biotite.

Quartz is found in varying amount, allotriomorphic, filling the space
between the other minerals. It is clear and sometimes occurs in large crystals.
Typical for the quartz are the very fine inclusions which are found in straight
lines in thin sections.

Accessory minerals: apatite in small and large prisms and needles is
enclosed in quartz and other minerals. Titanite in very large idiomorphic
crystals or in angular grains is very conspicuous. It is always present in a

rather large amount. Magnetite is often found together with apatite needles
in medium grains. Pyrite sometimes is met with. These accessory minerals
are the eldest components of the rock. Leucoxene and hematite occur as
alteration products of titanomagnetite and magnetite.

South of Provincial near the border with the Tuff-Formation several
aberrant diorites have been found. V. 119 (D. 16815), V. 120 (D. 16853),
and V. 121 (D. 16854) are strongly weathered rocks, very rich in quartz.
They are medium- to coarse-grained, greenish-browny coloured. Micros-
copically very large clear quartz crystals with many lines with liquid and
gaseous inclusions are conspicuous. The quartz is primary and forms about
one third to one fifth of the rock. The other components are plagioclase
and amphibole or their decomposition products. The plagioclases are
slender and broader prisms, and of medium length, or broad tabular ones ;
strongly altered into very dusty patches with sericite, or epidote and chlorite.
The average composition is andesine while much albite occurs too. The
amphiboles are partly replaced by epidote, chlorite and calcite. The plagio-
clase prisms and the amphibole sometimes form a rather coarse intersertal
texture with wide spaces filled in with quartz.

Cataclastic Phenomena. On several places the rocks of the Dio-
ritic Intrusion are affected by more or less strong cataclasis in conse-
quence of which the rocks become more or less parallel-textured. In
the beginning of the cataclasis, we see the quartz with undulatory
extinction and with a slight désintégration of the crystals. The plagio-
clases are bent and show undulatory extinction too. In a more advanced
stage of cataclasis mortar structure is produced. Large quartz and
plagioclase grains lie as lenticular relics in a squeezed, crushed, finer
matrix. The biotite becomes flaky and forms streaks in the rock, the horn-
blende désintégrâtes into many small grains and prisms, the magnetite is
ground almost to a powder, the apatite and titanite are crushed. All the
minerals and fragments of minerals show a parallel trend. Sometimes the
stress has affected the diorites to such an extent that fine grained eyed-
gntisses are formed. In these rocks a light yellow garnet occasionally is
found. The lenticular relics are orientated in the common direction. In
one sample the processes have been carried almost to the extreme. A
laminated structure results, closely resembling quot;flow-structurequot;, empha-
sized by trains of thin streaks of colour, representing the breaking down
of some particular mineral of the original rock. The lenticular relics arc
almost entirely ground away. We are deahng with mylonites.

SiOg-solutions have been present in the rock during the cataclasis,
as can be seen from the quartz veins and the plagioclases corroded by quartz
in the less strongly cataclastic rocks. Sometimes it is impossible to say,
whether the rock at hand was originally a common diorite, or a gneiss.

Some diorites must be mentioned for their slightly aberrant texture.
While in the common diorite a distinct crystalhzation sequence is present,

in the rocks from M. 667 (D. 16773, D. 16774), this sequence is rather
indistinct. The light minerals are about equigranular. The plagioclases,
which are well twinned and zoning, form short, broad tabular polygonal
crystals or crystals with undulating irregular rim. The quartz forms equally
polygonal grains. The amphiboles which mostly are hypidiomorphic too,
form larger crystals than the light minerals. The different minerals impede
each other mutually. By their arrangement the amphiboles cause a slightly
parallel texture which in the sample is still more conspicuous. The com-
position of this rock agrees mineralogically with quartz-amphibole-diorite.
Probably we are dealing with a gneissic facies of the diorite.

In the Southern part of the intrusion at L. 304 (D. 16497, D. 16498)
we found white-green, banded rocks, which are very interesting differen-
tiation products of the quartz-diorite-magma. Macroscopically they show
a clear parallel texture, marked by dark-green, and white bands, patches
and lenses. The dark bands and patches do not contain white minerals,
while in the light bands many dark green amphibole crj'^stals are visible.
Microscopically the rock appears to be a banded hornblende gneiss
with a strongly foliated texture. No crystallization sequence can be observed,
as most minerals are allotriomorphic. The plagioclases (about andesine)
are all arranged in the common direction and have an undulatory extinction.
Quartz in rounded grains is present. Amphibole occurs in a large amount.
Some hypidiomorphic crystals with elongated habit, are found between
the plagioclases and quartz. More important is the occurrence of amphibole
in compact bands and lenses. The colour, pleochroism, and extinction
points to common green amphibole. Cleavage is often well exhibited. In
the bands the crystals are all elongated, parallelly arranged, allotriomorphic.
Titanite, apatite, magnetite and zircon are accessory minerals. The light
bands can be compared mineralogically with acid quartz-amphibole-diorite.
These rocks have been affected by strong cataclasis, in consequence of
which they have a mortar-structure in the white bands. The plagioclase
and quartz have an undulatory extinction. The former is often bent, the
latter crushed at the periphery of the grains. The quartz intrudes sometimes
corrosively into the plagioclases. Hence a SiOg solution must have been
active during the cataclasis.

The hornblende in the dark bands shows, in consequence of the cata-
clasis, a rather strong undulatory extinction and also slightly crushed rims.
The undulose extinction of the hornblende proves the primary character
of this mineral. The rocks are primary banded by magmatic differentiation
and have been affected by cataclasis after the consolidation,

Diabasic quartz-diorite: green-brownish weathering, medium- to
fine-grained, holocrystalline rocks. L. 622 (D. 16617, D. 16618) is the best
sample. The rock is grayish green, medium-grained. Microscopically we
see a holocrystalline, hypidiomorphic rock, with a diabase-structure. The
constituant minerals are plagioclase, hornblende, biotite, quartz, with

titanite, apatite, magnetite, chlorite and calcite. The plagioclases are idio-
morphic, twinned prisms. They are clear, sometimes replaced by sericite
and epidote. The average composition is andesine, with a rim of albite at
the periphery of the crystals. Often at the borders of the plagioclases a rim
of myrmekite is formed by the corrosive action of quartz. The quartz fills
the space between the other minerals. Hornblende occurs in many hypidio-
morphic grains. With regard to the plagioclase it is allotriomorphic, with
regard to the quartz idiomorphic. It is green-pleochroitic, the same horn-
blende as we find in the amphibole-quartz-diorite. Biotite is green-dark or
brown pleochroitic; it is streaky. It takes up less room than the amphibole.
Titanite is found in large crystals, apatite in many needles, magnetite in
small grains. Chlorite is the decomposition product of amphibole and
biotite. Epidote is found in the plagioclases. H. 316 (D. 16938) is another
fine sample. This is a medium-grained rock. Microscopically we see a holo-
crystalline rock with ophitic texture. The main constituant minerals are
plagioclase, pyroxene, quartz, with their decomposition products, especially
chlorite, and accessory apatite and magnedte. The ophitic texture is formed
by the tabular plagioclase prisms with intersertal quartz and chlorite and
sometimes pyroxene. However, the pyroxene can also be idiomorphic with
regard to the plagioclase. The average composition of the plagioclase
corresponds with andesine. Broad twins are present. Microgranophyric
intergrowth with the quartz often is found. The andesine is dusty and
replaced by sericite and chlorite. The pyroxene is a colourless diopsidic
augite. Mosdy it is replaced by chlorite. In the intersertal spaces also chlorite,
which is the product of replacement of an original, yet unknown mesostasis,
occurs. Quartz is clear and allotriomorphic. Biotite, for a large part altered
into green pleochroitic chlorite, is found in a small amount. Apatite is
developed in very long fine needles. A rather large amount of magnetite
is present.

At V. 118 (D. 16850), V. 124 (D. 16859) and V. 125 (D. 16860) finer
grained, slightly porphyritic quartz diabases occur. The components are
alike of the above described rock. The only difference is the porphyridc
texture caused by a few larger crystals of plagioclase and mafics in a
predominant groundmass, showing a more or less clearly developed ophitic
texture. These rocks too are strongly weathered.

Hooibergitic Rocks. As already quoted, these rocks are found
only in the Southern part of the intrusive area. Here they occur in a
rather large amount, sometimes in exposures of 1 km. and more. They
form steep, elevated hills in the plany diorite landscape as a result of
selective erosion. Near L. 310 and L. 311 they are very well exposed.
Mostly the hooibergites have been, like so many other rocks in the
Dioridc Intrusion, affected by cataclasis and altered into quot;meta-hooi-
bergitequot;. A vcry conspicuous phenomenon is the occurrence of many
small and larger dikes of dioridc and aplidc rocks in the dark hooibergites.

Often fragments of the latter are found in these dikes (Plate, fig. 12).
Here we see very well proved that the more acid dioritic and aplitic
rocks are younger than the basic hooibergites.

As will be seen in the pétrographie description the hooibergites are
characterized by their texture and composition. Qualitative-mineralogically
the hooibergites are alike the diorites, but the quantitative distribution of
the components is quite different. Texturally the very large amphibole and
pyroxene crystals are typical. The Cuban hooibergites differ from the types
of these rocks as described and figured by Westermann (59) 1. by the
lack of quartz, 2. the quantitative distribution of the components, the
hornblende being always strongly predominant in the Cuban rocks. More-
over the state of preservation is different, as the Cuban rocks are much
more decomposed by weathering than the Aruban ones.

The fresh hooibergites are dark green, coarse-grained rocks, mainly
consisting of large, idiomorphic, dark green, lustreous hornblende crystals,
and very few smaller ones (amphibole prisms occur, measuring 21 X 13 inm.,
mostly they are about 9x3 mm., while small ones measuring 1 mm. are
very rare). Between these amphiboles a white quot;groundmassquot; occurs. Apart
from the dark, green, lustreous hornblendes sometimes dusty, green, smaller
pyroxene crystals occur. We are dealing with pyroxene-hooibergite then.
With the intergration-stage in the sample of L. 302 we found 62.65 %
amphibole, 28.22 % pyroxene, 9.07 % plagioclase.

Microscopic description of hooibergite. The constituant minerals are
amphibole, plagioclase, epidote, zoisite, magnetite, apatite and zeolite. The
amount of amphibole is predominant. It is the only idiomorphic mineral.
It is found in large isometric, long prismatic crystals, and in smaller ones.
Both are of the same generation, as the smaller ones work in with the bigger
ones. The smaller are idiomorphic with regard to the light minerals too.
The hornblendes are green, light-green pleochroitic, scarcely twinned. Very
conspicuous are the large amphibole crystals often with very few or wit-
hout any inclusion or any weathering, while the plagioclases are strongly
altered. However, some patches of coarse epidote and magnetite grains arc
found in the amphibole crystals. The altered plagioclases are allotriomorphic,
dusty, sometimes polysynthetically twinned. The composition ranges from
albite to andesine. Once dusty orthoclase has been found. The plagioclases
are very strongly decomposed by weathering. They are dark dusty, someti-
mes entirely sericitized, sometimes with large grains of zoisite and epidote.
Once titanite has been found. Apatite occurs in small prisms and needles
in the plagioclase. Spheroidal zeolites are present as hydrothermal minerals.
Quartz is entirely lacking.

Microscopic description of the pyroxcne-hooibergites. The most
important minerals are hornblende, pyroxene and plagioclase. The large,
homogeneous, sometimes twinned hornblendes are similar to those of the
hooibergites, light-green to green, sligthly pleochroitic, beautifully cleaved.
Also the idiomorphism of the smaller and large crystals with regard to the

plagioclase is the same. Very few inclusions of magnetite and epidote and
weathered plagioclase occur. Often amphibole is intimately intergrown
with pyroxene. In the prismatic zones the two minerals border at each other
with straight faces. In section about perpendicular to the prismatic zone both
minerals become under crossed niçois extinguished at the same time. The
pyroxene is colourless diopsidic augite. It occurs as large tabular crystals.
Rarely the crystals are built up entirely by pyroxene only, mostly they are
intergrown with amphibole, both showing the typical cleavage of the
respective minerals. They are both very clear and it is obvious that they
crystallized simultaneously side by side. With regard to the plagioclase the
pyroxene is idiomorphic. The plagioclase occurs in a rather small amount.
The average composition is albite-andesine. Once a clear polysynthetically
twinned bytownite has been found. The plagioclases are sericitized or
saussuritized, and very dusty. Large idiomorphic zoisite is found in the
quot;groundmassquot;. Accessory minerals are apatite, titanite and magnetite. Quartz
is lacking entirely. The fact that bytownite is found, is remarkable, for now
we cannot be sure about the original composition of the plagioclases.

About the distribution of quartz-free hooibergites and pyroxene hooi-
bergites nothing can be said. Fresh samples of both types were found toge-
ther. In the metamorphosed hooibergite, which form the bulk of these
rocks, it is difficult to state whether they are altered hooibergites or altered
pyroxene-hooibergites. Westermann says on page 50 quot;so all the hooibergites
might be metamorphosed pyroxene-hooibergitesquot; as he finds that near the
contact with dioritic and aplitic dikes the augites are altered into amphiboles.
The same phenomena are found in Santa Clara (see below). However, the
occurrence in one rock of large clear primary hornblende together with pyro-
xene, and the way in which they are intergrown induces me to assume really
primary hornblende-hooibergite and to deny the above mentioned possibility.

The hooibergites are plutonic rocks, older than the diorites. They were
already in an advanced state of consolidation when the dioritic magma
intruded, as can be seen from the contactmetamorphic phenomena, described
below and from the inclusions described above. The mineralogical com-
position points to their belonging to the dioritic magma. As Westermann
(59) already mentions, probably the hooibergites were the first differenti-
ates of the intrusion in the sense as described by Daly (14, p. 347).
In this conception the hooibergites are the first chilled parts of the magma
in the roof of the batholith. The fact that we find magmatically stooped
inclusions of the country rocks (e.g. mcta-porphyrites as described below)
near the hooibergites on several localities supports this supposition. The
hooibergites show resemblance with gabbros, having, qualitatively corres-
ponding mineral composition. However, again the texture and quanti-
tative mineral composition are obviously distinct.

Gabbro-diorites. We did not find real fresh unaltered gabbros in
Southern Santa Clara. However, there arc more or less contact-metamorphic

rocks, which are obviously altered gabbro-diorites. They occur like the
hooibergites in the southern part of the intrusive area, and are also
strongly cut by acid dioritic and aplitic veins. Hence they are older than
the diorite intrusion. L. 278 (D. 16465) is the best sample, which is a dark
green, coarse-grained plutonic rock with long amphibole prisms (measuring
up to 1 cm). Microscopically we see a coarse-grained hypidiomorphic
gabbroic texture. The main constituent minerals are plagioclase, pyroxene,
amphibole, magnetite and titanite. No quartz is present.

The rock is slightly affected by contact metamorphism. A small amount
of the pyroxene is replaced by uralitic hornblende, and the original contours
of the minerals are more or less disturbed by corrosion. The plagioclase
forms large tabular crystals with polysynthetical twinning, which often wed-
ges out. The average composition ranges from andesine to labradorite. The
plagioclases are slightly dusty, especially in the centre of the crystals. Some-
times they have an undulatory extinction. Locally the plagioclases are strongly
altered by saussuritization. The pyroxene is colourless diopsidic augite. It
forms hypidiomorphic broad tabular prismatic crystals. Often it is inter-
grown with amphibole and sometimes it is repladed by amphibole. Horn-
blende is light green pleochroitic, idiomorphic with regard to plagioclase,
having sometimes inclusions of idiomorphic plagioclase crystals. Hornblende
and augite are of the same age, as they are intergrown with one another.
Some large amphibole crystals show a dense, very regular crowd of black
ore inclusions, parallelly arranged, perpendicular to the prismatic zone.

It is difficult to differentiate this intergrown amphibole from the
secondary amphibole. When the intergrown amphibole is primary, we see
in the primatic zones both minerals bordering on one another with straight
faces. Both minerals are very regularly distributed in the composed crystals.
Uralitic amphibole is irregularly shaped, mostly found at the periphery of the
augites. Moreover in the last case the two minerals are not so clearly disting-
uished from one another as they are slighlty dusty and the amphibole
is light coloured. Epidote is sometimes found in a small amount, probably
as a by-product of the uralitization of augite. A few large polyangular
crystals of titanite and many smaller of magnetite occur. Apatite is present
in a small amount.

At L. 279 (D. 16469) a contact metamorphic rock in a rather advanced
stage of metamorphism, with a relic-porphyritic texture and a decidedly
gabbroidic mineral composition has been found. As rests of phenocrysts
we find pyroxenes, amphiboles, and plagioclases. The pyroxenes are of
different composition. A lot of very large colourless diopsidic augite crystals
with a hooibergitic habit occurs. This augite is partly or wholly replaced by
light green, pleochroitic, uralitic amphibole, while often a slight concentra-
tion of magnetite is found in the phenocrysts. Moreover, light coloured
pink-grayish to green pleochroitic hypersthene is found. It is idiomorphic,
clear, unwëathered and without inclusions. Some large plagioclase crystals
occur, ranging in average composition from andesine to labradorite with

many inclusions of amphibole and pyroxene grains forming a poikiloblasdc
texture. The groundmass is a totally recrystallized medium-grained, grano-
blastic mosaic of plagioclase, amphibole and diopsidic augite crystals. Small
and larger grains of magnetite and some pyrite are present.

A third type of plutonic rock of the same nature as the hooibergites
and gabbros occurs, namely an olivine-pyroxenite (D. 16467). This is
a dark green to black coarse-grained rock. Microscopically it appears to
have a hypidiomorphic texture. The large crystals impede each other and
there is no distinct sequence of crystallization. The main consituent minerals
are pyroxene and olivine. The pyroxene is partly a colourless, rhombic one,
with a low polarisation colour. It has been partly replaced by almost
colourless to light green dusty amphibole. Much more space is taken by
monoclinic pyroxene, which is diopsidic augite and diallage. These too
sometimes are replaced by amphibole. Olivine occurs in large crystals in
and between the other minerals. It takes more space than the rhombic
pyroxene and less than the monocHnic pyroxene. It is partly serpentinized.
Accessory magnetite is present. This rock is also very probably a basic
differentiation of the dioritic magma.

In the diorite intrusion E of Gavilan on some places hornblendite
is found. The green, coarse-grained rocks are built up almost entirely of
hornblende, wich is dark-green, pleochroitic and shows a typical cleavage.
The crystals are large, hypidiomorphic, broad prisms. Epidote and chlorite
are present in small amounts. Accessory magnetite and titano-magnetite
is found.

Meta-hooibergites. The large bulk of these basic plutonic rocks,
which consolidated before the main dioritic intrusion has been affected by
contact metamorphism caused by the intruding magma and by dynamo-
metamorphism caused by orogenic activity during and after the intrusion.
The augite is replaced then by amphibole and epidote, the amphiboles
pass into innumerous small needles of uralite, and many new small
idiomorphic crystals are formed. The plagioclases are cleared up and, in
a further stage, recrystallized into polyangular allotriomorphic grains and
crystals. If the dynamometamorphosis is strong a definite foliation is
found, emphasized by the amphiboles.

At L. 302 (D. 16493, D. 16494) we sampled a dioritic dike enclosing
fragments of hooibergite and isolated hornblende crystals. The latter are
easily distinguished from the amphiboles of the diorite being of a much
larger shape. As can be seen from the photograph (Plate, fig. 12) both rocks
are sharply bordered. Microscopically we see normal quartzfree hooibergite
enclosed in slightly linear textured, cataclastic quartz-hornblende-diorite.
The hooibergite does not contain any pyroxene, although in samples from
the same locality pyroxene-hooibergites are found. The amphibole of the

enclosed hooibergite is partly primary and partly secondary, replacing the
pyroxene. The amphiboles are sHghthly resorbed at their margin and some-
what dark by ore-inclusions, but on the whole their appearence is the same
as in the hooibergites. The dioritic dike-rock is normal quartz-amphibole-
diorite, with andesine, quartz, granophyric intergrowth between these
minerals, amphibole, epidote, titanite, some biotite and magnetite. It is
cataclastic, showing undulatory extinction and mortar structure of the
minerals. Probably the irregular contour of the enclosed fragments may
be caused by the cataclasis. The only effect of contact-metamorphosis here,
is the amphibolitization of the pyroxene. It was compHcated by the later
cataclasis.

In a more advanced stage of metamorphism the hooibergites become
dark-green, showing a pseudo-porphyroblastic texture, caused by the
occurrences of many large amphibole crystals which have been saved from
desintegretion by metamorphism, lying in a green, fine-grained quot;ground-
massquot;. The latter may show foliation. Mostly, however, no special texture
can be seen. Microscopically these rocks are immediately recognized as
altered hooibergites by the remnants of the large amphibole cr^'stals. We
find namely the large, prismatic crystals as in the hooibergites. At the
ends of thé prisms and, in a smaller amount, on their prismatic faces, the
amphibole crystals are resorbed and desintegrated into many small amphi-
bole needles and prisms and into uraUtic needles, which together with the
recrystallized clear albite and epidote form a granular medium-grained
quot;groundmassquot;. The albite forms polyangular to rounded isodiamctrical
grains, which are sometimes twinned. The amount of plagioclase depends
on the original composition of the hooibergite. In some cases the amount
of leukocratic minerals decreases and it is even found that no leucocratic
minerals at all are present. Very probably the quot;groundmassquot; is squeezed
out then. In these cases we find between the large amphibole crystals a
fine-grained, quot;fluidalquot; mass of amphibole grains, and small prisms. The
large amphibole crystals often show internal recrystallization, new small
slender prismatic amphiboles being formed in them. Sometimes this recry-
stallization is excessive and we find a dense crowd of amphibole needles and
prisms in the original large crystals. In the amphiboles are found poikilitic
inclusions of epidote, calcite and albite. The epidote of the quot;groundmassquot;
forms crowds of isodiometrical, medium-grained crystals. In the pyroxene-
hooibergite the augite is mostly totally replaced by amphibole and epidote.
A rough calculation shows that after uralitization of the diopsidic augite
we can expect as much uralite as epidote or slightly more. This agrees well
with our samples. In some cases, when the metamorphosis was not very
strong we see large crystals of colourless augite with a rim of amphibole.

If the dynamometamorphosis was predominant over the contact meta-
morphosis the recrystalhzed amphiboles became slender prisms, the quot;ground-
massquot;, arranged parallelly to a common direction together with slightly
elongated albite and epidote, producing a quot;fluidalquot; texture. Some large

plagioclase crystals contain small inclusions of ampliibole and epidote.
Sometimes the epidote of the groundmass is affected by strong myrmekite-
like corrosion by albite.

Amphibolitic rocks. In the Dioritic Intrusions on the South-
side many amphibolitic rocks of various types have been found. They
could be separated from the metahooibergites, as the last ones always are
easily recognized by the relic hornblende crystals of the hooibergite. The
origin of the different types cannot be stated with certainty. The ortho-
nature is almost sure. There are amphibohtes very probably originating
from gabbros or hooibergites or hornblendite, recognizable by the mineral
components, the chemical constitution and the relic textures. On the other
hand amphibohtes, very probably originating from magmatically stooped
country rocks (porphyrite) are found. Finally of some amphibohtes the
origin is obscure. Several amphibohtes are described in the fohowing.

At M. 255 (D. 16720) a medium-grained, green, holocrystahine amphi-
bolite, consisting of amphibole, pyroxene and plagioclase is found. Micro-
scopicahy the rock shows a granoblastic texture. There are some large
hornblende crystals carrying plagioclase inclusions. They are probably
relics of the original rock. The great bulk of the rock is formed by smaller-
grained, granoblastic, light green amphibole. The crystals are prismatic or
isodiametrical quadrangular, and hexagonal, carrying often plagioclase
inclusions. A small amount of diopsidic augite is found, almost always
enclosed in or surrounded by amphibole granoblasts. These augites, which
are smaller in size than the hornblende, are probably also relics of the original
rock. Plagioclase is the second mineral of the rock and occurs in isodia-
metrical, often twinned, clear crystals. The average composition ranges
from andesine to labradorite. Often poikilitic amphibole inclusions arc
found. For the chemical composition of this rock sec analyse no. 3 on
page 51. This suggests an ortho-rock of basic composition between the
gabbro-noritc and pyroxene-hornblenditc.

The structure of the samples from V. 356 (D. 16878), L. 437 and L. 438
(D. 16569—D. 16579) is very similar to that of the sample of M255. The
amount of amphibole is larger; epidote is present and pyroxene is lacking.
In this rock also allotriomorphic chlorite and magnetite occur, which, in
consequence of dynamomctamorphosis form streaks in the rock. In these
cases the amphibole and plagioclasc are arranged in a common direction
and the rock is foliated. These rocks arc cut by albite veins and some of the
plagioclases arc albitizcd. The origin of these rocks is not clear.

At A. 495 (D. 17103) and A. 497 (D. 17105) another amphibolite
occurs. The rock is light-green, pscudo-porphyroblastic, foliated. Micros-
copically we see large, broad hornblende prisms mostly not parallel to the
common direction. They are often poikilitically sieved by many plagioclase
inclusions, especially at the periphery of the crystals. These amphiboles are
not porphyroblasts, but relics of the original rock. They are situated in a

quot;groundmassquot; which is for the smaller part granoblastic and for the larger
part nematoblastic to lepidoblastic. It is built up by small and large amphibole
prisms and elongated clear plagioclase grains. The amphibole is light-green
and pleochroitic. The average composition of the plagioclase is andesine to
labradorite, while albite and oligoclase also are present. The rocks are cut
by aplitic veinlets. The large primary amphiboles suggest a gabbroic or
hooibergitic origin for these rocks.

In other rocks the texture is strongly lepidoblastic and no more large
lenticular relics of primary amphiboles are present. H. 297 (D. 16923,
D. 16924, D. 16926), H. 299 (D. 16927) and H. 302 (D. 16933) are rocks
of this type. These rocks are finely foliated. Microscopically they appear
to be totally recrystallized rocks with a very fine linear texture, caused by
the very regularly distributed, equigranular crystals of amphibole and
andesine. These crystals are elongated, rather small, and very clear; they
carry poikilitic inclusions of each other. Magnetite occurs in smaller grains,
between or enclosed in the other minerals. Epidote occurs in these rocks
in a certain amount. Sometimes it is found together with calcite and ore
and sericite in patches, which originally have been plagioclase crystals.

Finally amphibole-schists have been found, existing almost entirely of
green pleochroitic hornblende. This mineral is present in fine needles, and
prisms or in tabular elongated prisms. Chlorite is often found. Porphyro-
blastic texmre, marked by large hornblende and chlorite (pennin) crystals
occurs. In many amphibolites a larger or smaller amount of secondary
epidote is found. If the amount of epidote and hornblende is about equiva-
lent, we are dealing with epidote-amphibolite. At L. 287 (D. 16975—
D. 16977) e.g. a fine-grained highly foliated, microgranoblastic epidote-
amphibolite is found.

Quite different from the above mentioned amphibolites are the pyroxene-
amphibolites from V. 115 (D. 16848), L. 438 (D. 16577), L. 570 (D. 16608),
and M. 277 (D. 16725). These rocks show macroscopically alternating
lenses and bands of a dark- and lighter-green colour giving a schistose
impression. Microscopically it appears that these colours are caused by
green hornblende, and almost colourless pyroxene. The texture is a quot;Hornfels
Structurquot;. The minerals form isodiametrical or slightly elongated grains.
The main constituant minerals are amphibole, pyroxene and plagioclase.
The different bands appear to be built of plagioclase with predominant
amphibole or in other bands with predominant pyroxene. Plagioclase is
clear, never twinned, in composition ranging from albite to andesine, with
the latter prevailing. In the bands rich in augite the plagioclase occurs in
a larger amount than in the amphibole-bands. The amphibole is green,
pleochroitic. This mineral shows most of all an elongated habit of the
crystals. It is largely prevailing over the plagioclase and pyroxene together,
at least in the amphibole bands. The pyroxene is colourless diopsidic-augite.
Accessory magnetite grains and apatite needles are present. Epidote is
sometimes found replacing the augite. On the whole these rocks are very

fresh. About the origin of them nothing can be said. Very probably these
rocks, which are found as inclusions in the dioridc intrusion represent
metamorphic rocks in a rather advanced stage of metamorphism.

Quartz-diorite-porphyrite. Many rocks of this type were sampled
in the Northern part of the intrusion, especially near the contact with the
Tuff Formadon. Three dikes of this rock-type were found in the Tuff
Formation near the contact. These otiginated very probably from the main
intrusion, which lies close below the surface and below the rocks of the
Tuff-Formation there. The other quartz-diorite-porphyrites occur as dikes
in the quartz-diontes. Macroscopically the rocks are grayish-white, mosdy
greenish or brownish weathering. Quartz and plagioclase phenocrysts are
visible in a finegrained to aphanitic groundmass. Microscopically we see
rather acid porphyrites, with a more or less strongly predominant ground-
mass. The phenocrysts are quartz and plagioclase; often rests of mafic
phenocrysts are found as aggegrates of chlonte, calcite, and sometimes
epidote or brown oxidic ore. Unaltered hornblende or biotite pheno-
crysts never are found. Quartz phenocrysts occur sometimes in a larger,
mostly equal or in a smaller amount than the plagioclases and in a
larger amount than the altered mafic phenocrysts. Apatite, titanite and
magnetite are accessory minerals.

The plagioclase phenosrysts are short or long, simply twinned prisms,
which often are found in groups. In the fresh, unaltered ones they border
sharply with the groundmass. The average composition ranges from albite
over albite-oligoclase to andesine. Often they are vcry dusty and the
crystals are rounded off, this caused by the groundmass which works in
with the plagioclase phenocrysts. The plagioclase is altered in many different
ways by weathering. We sec albitization, chloritization, sericitization and
epidotization in varying amounts. The quartz forms beautifully clear, mosdy
unaltered, idiomorphic phenocrysts, carrying lines of inclusions. Often they
arc rounded off, and pardy resorbed by the groundmass, sometimes showing
a broad resorption rim. In some thin-sections the quartz phenocrysts are
broken and the fragments lie close to each other, with between them ground-
mass. Flence, during the intrusion the phenocrysts arc broken and afterwards
the groundmass consolidated between the fragments. Here, locally we have
protoclastic structure. The pardy consolidated magma must have been
affcctcd by stresses and this may be considered as an indication for the
coincidence of an orogenesis and the intrusion.

The aggregates of alteration products of the mafic minerals sometimes
show the form of amphibole prisms. They are mainly composed by calcite
and/ or chloritc. The calcitc may be microcrystalline or medium-grained.
Chloritc forms dark-green, not pleochroitic, irregularly shaped grains. In
other places this mineral is obviously a light green pleochroitic alteration
product of biotite. The groundmass is holocrystallinc, fine- to small-grained
The texture is panallotriomorphic-granulose, or hypidiomorphic-micro-

granitic. The components are quartz and plagioclase and often chlorite,
calcite, oxidic ore and sometimes small, green, pleochroitic biotite flakes.
In the last mentioned microgranitic groundmass the plagioclases form
small laths, and sometimes microgranophyric intergrowth with the quartz
is found. Chlorite may be found then in very streaky leaflets between the
other minerals. The groundmass is often altered; sihcification is found and
in other cases it is replaced by a fine calcite and sericite powder. In L. 318
(D. 16512) the altered groundmass is a fluidally arranged isotropic chlorite,
calcite and sericite mass.

Many of the quartz-diorite-porphyrites are totaUy sihcified and form
quartz dikes with a rehc-porphyritic texture.

Hornblende-diorite-porphyrites. We found two different types
of these rocks. At A. 492 a hornblende-diorite-porphyrite with a crypto-
to micro-cr)'^stalline groundmass occurs, while on A. 497 (D. 17106) and
H. 630 (D. 16971) rocks of this type with a holocrystalhne, rather coarse
groundmass are found.

The hornblende-diorite-porphyrite of A. 492 (D. 17101) is a hght
coloured rock with dark phenocrysts in a white groundmass. Microscopically
we see large and smaller phenocrysts of amphibole and plagioclase in a
crypto- to micro-crystalhne groundmass consisting of a fine panallotrio-
morphic aggregate of a colourless minerals (probably plagioclase and
quartz) with epidote and shghtly larger amphibole and magnetite microlites.
The amount of the groundmass and the phenocrysts is about equal. The
plagioclases are clear, and sometimes strongly weathered, idiomorphic,
isodiametrical or prismatic phenocrysts. They show twinning and zoning.
If decomposed, they are weathered into epidote, calcite and sericite. The
average composition of the plagioclase is andesine. The amphibole pheno-
crysts are dark green, pleochroitic, idiomorphic and often twinned. Some-
times they carry several inclusions of ore or epidote. By weathering they
are replaced by chlorite or epidote with ore. Magnetite is an accessory
mineral in medium-grained crystals.

H. 630 is a light, porphyritic, grayish rock with plainly visible plagio-
clase, quartz, amphibole and biotite phenocrysts. Microscopically we sec
that the amount of phenocrysts is about equivalent with the groundmass.
The phenocrysts are p.p. broken into angular fragments. The plagioclases
are clear, isodiametrical, and prismatic crystals, often with twins or zonal
arrangement. The average composition ranges from andesine to labradorite.
Some smaUer, clear quartz phenocrysts arc found. Amphibole forms large
and smaller idiomorphic grains of green pleochroitic hornblende in a small
amount. Biotite occurs is a larger amount than amphibole and a smaller
than the plagioclase. It occurs in large and smaller, brown, plcochroitic
crystals. The groundmass is a dusty, hght aggegratc of quartz grains,
plagioclase laths, biotite flakes, hornblende scales, apatite needles, and ore
grains.

A. 497 is à amphibole-diorite-porphyrite onJy differing from the
common diorite by its porphyritic texture. The mineralogical composition
is the same as in the diorite.

Leucocratic dike rocks. To this group several light coloured dike
rocks belong. They are partly of magmatic origin (diorite-aplite, grano-
diorite-aplite, plagiaplite), pardy of postmagmatic origin (quartz-epidote
rocks, quartz-rocks, and epidote-rocks). They form clearly dikes in the
hooibergites, gabbros, amphibohtes and quartz-diorites. Mostly these dikes
are narrow, sometimes broad. At M. 252 a very large dike measuring 15 m
in diameter is found.

The aplitic rocks are grano-diorite-apHte, plagiaphte and diorite-aplite.
They are holocrystalline, panallotriomorphic, medium- to coarse-grained,
white, yellowish and pink rocks. They consist mainly of felspars and quartz.
The dark minerals are biotite and ore, occurring in small numbers and
small crystals. Quartz is white and felspar sometimes pink. Microscopically
the granodiorite-aplites show the following components: orthoclase,
microcline, albite, oligoclase-andesine, quartz, granophyric intergrowth of
albite and quartz, microcline-perthite, myrmekite, biotite, garnet, aptatite
and magnetite. Secondary epidote, chlorite and limonite are found. The
quartz occurs in a smaller amount than the plagioclase and in a larger amount
than the kalifelspars. Myrmekite is found on the border of quartz and
microcline or plagioclase. The granophyric intergrowth of quartz and
albite sometimes is rather coarse, almost graphic. Biotite occurring in small
flakes, mostly is weathered into lightgreen, pleochroitic chlorite.

In the plagiaplites no kalifelspars occur. Biotite and muscovite arc
present at the side of spheroidal light-green chlorite. Epidote is found in a
somewhat larger amount than in the granodiorite-aplites.

One plagiaplite must be mentioned separately for its special texture.
At L. 314 (D. 16507) we found a white dike-rock, which microscopically
shows a typical texture. Idiomorphic albite and oligoclase prisms lie in and
around allotriomorphic quartz grains and then form an almost interscrtal-
like texture. The quartz is clear, the plagioclase is dusty and sericitizcd.
Magnetite and hematite are present in this rock.

The aplites arc affectcd by cataclasis on several places, and the same
structures, as described in the other dioritic rocks arc found. The extinction
becomes undulatory, the crystals are broken at the margin and mortar
structure comes into being, the désintégration continues and lenticular
relies of the original ctystals lie in a mylonitic matrix of crushed grains.
SiOa solution was mobile, and secondary quartz is found with new grains
and corrosive in the primary crystals. The brittle nature of the aplitic rocks
was very capable for mylonitization. The aplites yielded the most striking
examples of gneissification and mylonitization. On the Plate the figures 10
and 11 show strongly cataclastic aplitic rocks.

The post-magmatic dike rocks are light-green to green, on weathered

surfaces with a brownish colour. Once white quartz amygdales in the green
rock have been found. These rocks are built of varying amounts of quartz
and epidote. They are small-, medium-, and coarse-grained. Almost entirely
epidote is found in H. 248. The epidote crystals are coarse and show poly-
angular contours. This mineral occurs together with green, pleochroitic
chlorite and titanite. In H. 251 (D. 16910) and M. 185 (D. 16675) epidote is
predominant over quartz. H. 251 has amygdales, filled in with clear quartz
and at the periphery with clear polyangular, epidote, sometimes radially
arranged, in prisms. These amygdales lie in a quot;matrixquot;, which consists of
very irregular medium-grained, dusty epidote and some quartz. A. 489
(D. 17097) is a medium to fine-grained quartzitic rock with chlorite and
epidote veinlets. In A. 292 (D. 17013) and M. 192 (D. 16684) the small-
grained quartz and epidote are equivalent. M. 188 (D. 16678) is an epidote-
chlorite-quartz-rock, with epidote predominant. Chlorite occurs together
with titanite and probably is altered biotite from the country rock. Mag-
netite is present as an accessory.

Lamprophyric dike rocks. Several malchites, some spessartites
and one odinite have been found. We did not find a special distribution
of occurrence of the lamprophyres. They are found as dark dikes in the
quartz-diorites.

The malchites are small- to fine-grained, green rocks. Microscopically
the rock mainly consists of plagioclase, hornblende and quartz. The
amount of dark and light minerals is almost equal. The texture is
holocrystalline, hypidiomorphic, fine- to medium-grained, granular, while
some large crystals of amphibole and plagioclase occur. The plagioclase is
andesine-labradorite and albite. The albite always is allotriomorphic.
Sometimes it forms large crystals, enclosing rare idiomorphic amphibole
and plagioclase prisms. This is the same peculiar texture as we also found
in the quartz-diorite in several samples. The common texture is determined
by hypidiomorphic equigranular prisms of amphibole and plagioclase.
The amphibole often is idiomorphic too. The plagioclasc forms small laths
and short twinned prisms, which are mostly idiomorphic with regard to the
quartz, while sometimes quartz and plagioclase work in with each other.
Quartz is clear; plagioclase slightly dusty, sericitized or replaced by epidote
and chlorite. The amphibole is light green, pleochroitic. It is always idio-
morphic with regard to the quartz. Titanite grains, small magnetite grains
and small apatite needles are found accessorily.

The spessartite from A. 493 (D. 17102) and L. 288 (D. 16478, D. 16479),
is texturally, and structurally very much alike the malchites. It differs from
them by the occurrence of orthoclase in allotriomorphic grains.

The odinite from H. 306 (D. 16935) is a fine-grained, brownish green
rock. Microscopically it consists of hypidiomorphic plagioclase laths and
fine brownish idiomorphic amphibole needles and chlorite grains which are
probably altered pyroxene. The texture is hypidiomorphic.

Foreign inclusions in the dioritic intrusion. Amphibolites,
differing in texture and composition from all the above described ones are
found as inclusions in the diorites at L. 277. Dark green porphyritic rocks
with a dense groundmass show microscopically augite phenocrysts replaced
by amphibole at their periphery, in a panallotriomorpbic, medium-to fine-
grained groundmass, built of amphibole and felspar. The amphibole is dark
to light green, pleochroitic, irregularly shaped, often replaced by epidote
or chlorite. In spite of their irregular shape sometimes they suggest by their
arrangement, a slighdy linear texture. The felspars form isodiametrical
fine-to medium-grained crystals which are more or less clear. Orthoclase,
microcline, albite and oligoclase are found. Apatite and titanite are
accessory minerals. The phenocrysts are pnmarj.^ diopsidic-augite, more
or less replaced by amphibole, with many poikilitic intrusions of felspar
and amphibole. Many amphibole phenocrysts show an augite shape. The
augites are like those found in the porphytites of the Tuff-Formation.
The groundmass is quite different from those in the other amphibolites,
by its more evenly distributed, fine-grained, equigranular granoblastic tex-
ture. These features suggest an original porphyritic rock from the Tuff-
Formation, altered by contact metamorphism. These rocks too are cut
by leucocratic dikes.

At H. 296 a quartz-sillimanite-mica-schist is found, together with
strongly, finely foliated amphibolites. The rock is feltlike, light-brown.
Microscopically it appears to consist of quartz, brown mica, sillimanite, and
accessory magnetite. The quartz occurs in clear, allotriomorphic, large
grains, the sillimanite in long needles, the mica in light-brown, pleochroitic
crystals. The foliated structure is caused by the sillimanite and mica. Oxydic
ore is, in large and small grains, irregulariy spread in the rock. This a rather
strongly contact-metamorphic rock, the origin of which is unknown.

At L. 291 (D. 16486) an amphibole-biotitc-plagioclase-schist is found
with many biotites. The rock is foliated, dark green. Microscopically it shows
a foliated texture, caused by the streaks of biotite and the elongated green
amphiboles. Biotite is light brown, pleochroitic. Occasionnaly it is found
within the amphibole crystals. The amphibole is common green hornblende.
The amount of both are equivalent, and together they take up more space
than the andesine, which is the only light mineral. Some crystals of rhombic-
pyroxene arc present. Magnetite and hematite arc accessory minerals. Chlo-
rite and many coarse grains of epidote are decomposition products of the
mafics. The origin of this rock is unknown.

At M. 237 (D. 16704) a calc-silicate-hornfels occurs as inclusion in the
diorite. The origin of this rock is not known. It has a foliated porphyro-
blastic structure with a medium grained granoblastic groundmass, while
the phenocrysts arc highly poikiloblastic. The porphyroblasts are amphiboles
or replacing calcite and epidote, the latter allotriomorphic or pseudomorphic
after amphibole. The amphibole is secondary, tabular, its character, however,
is not uralitic. Probably this is a result of a higher grade of metamorphism

than in the uraUte-porphyrites. The groundmass is composed of clear micro-
dine, albite, and andesine as ahotriomorphic rounded polygonal grains;
and idiomorphic yellow garnet surrounded by calcite. Magnetite, pyrite and
zircone are found, too. Calcite fills the spaces between the other minerals.

Habana Formation.

The name quot;Habana Formationquot; was given by Palmer (32) for
Upper Cretaceous beds near Habana. M. G. Rutten apphed the same name
for all the Upper Cretaceous beds on the island, which may vary rather
strongly in lithological and petrographical character, but which contain the
same fauna and are of the same age.

In Southern Santa Clara this formation outcrops on many places in
rather small exposures. The extension has been much larger than is found
now, as can be seen from the relics of the Habana Formation lying on the
Tuff Formation on several places in the centre of the tuff area. Probably it
has covered very large parts of island and it has been thoroughly affected
by denudation during the Lower and Middle Eocene.

The rocks of the Habana formation are chiefly found on the rims of
the Tertiary basins, where the transgressive Tertiary rocks do not cover
them by overlapping.

The age of the Habana Formation is determined by the occurrence of
the foraminiferal genera Lepidorbitoides and Orbitoides which in Europe are
index-fossils for the Maastrichtian beds. Moreover a large fauna is found
of Globigerinidae, Vaughanina, Camerina, Rudists, Corals, Echinids and a
small amount of Radiolaria. In the palaeontological list the species will be
enumerated with their finding-places.

The rocks of the Habana Formation are transgressive over the diorites
(A. 486) and over the Tuff Formation on many places. Detritical material
of these two formations is found in the conglomerates of the Habana For-
mation, e.g. fragments of porphyrites and spihtes of the Tuff Formation and
of quartz-diorites and aplites of the diorites. Very often these fragments
are found together with several typical Upper Cretaceous fossils.

The structural unconformity between the Habana Formation and
the Tuff Formation can be seen clearly on the map in the surroundings
of Soledad, SE. of Palmira, N. of Jutia and around Fomento. In this last
mentioned region the Habana Formation forms a synclinal.

In the Western part of Southern Santa Clara it is difficult tot state
whether the Habana Formation and the Upper Eocene arc structurally
conformable or unconformable. Stratigraphically there is a large gap between
both formations. In the Eastern part of the Provnice a structural uncon-
formity occurs, as can be seen from the map NW. of Cabaiguan. Here the
strikes of the Tertiary and Upper Cretaceous strata are divergent.

The structures of the Habana Formation in the Western part of the
Province are simple. In the Eastern part near Fomento and Guayos, and

North of Zaza del Medio, the folding is much stronger and we see steep
synclines and anticHnes. On the Carretera Central e.g. South of Guayos,
this is well exposed. South and East of Fomento at V. 332 and L. 573 and
also at V. 307 South-East of Guayos the rocks of the Habana Formation
are even overturned.

The Habana Formation North of Jutia is to the North bordered by
a fault, which in the landscape is emphasized by a steep slope of the hill
consisting of rocks of the Habana Formation.

The Habana Formation comprises limestones, microconglomeratic and
tuffaceous limestones, marls, crystal-tuffs, vitric tuffs, and probably porphy-
rites too. The vitric tuffs are found only at two localities. All the other
types of rocks, except the porphyrites, are found in the whole district,
irregularly alternating with each other. The volcanic tuffs and the tuffaceous
limestones prove a volcanic activity during Upper Cretaceous times. M.
G. Rutten describes intrusions of porphyrites in the Habana Formation
and concludes that: quot;We may consider the volcanic activity, during the
sedimentation of the Habana Formation, as the waning of the igneous
activity that formed the earlier dioritic intrusions.quot; In the Southern part
of the Province no porphyritic rocks have been sampled in the Habana
Formation, although it must be mentioned that, on the course from Guyaos
(Carretera Central) to the NE. and in a smaller amount on the course from
Zaza del Medio to the NE. many large rounded porphyrite blocks are
irregularly distributed in the region of the white marls and limestones, which
in consequence of their lithological and tectonical habit very probably belong
to the Habana Formation. As these quot;orientation courses'' were very long
ones, no samples could be collected; so we are not sure about the age and
the character of these porphyrites.

Vitric tuffs are found at V. 367 (D. 16882, D. 16883), and V. 369
(D. 16884). They arc white-yellowish or light purplewhitish, in one sample
cut by many very fine epidote veins. They are distinguished from the
vitric tuffs of the Tuff Formation by their colour. Microscopically we see
cloudy glasstuffs, p.p. calcified, p.p. chloritized and, in one case, cut by
epidote veinlets. V. 367 carries large inclusions of epidotized and silicified
rock fragments and separated crystals.

A. 442 (D. 17062) is a purple, dense clayish rock showing microscopi-
cally a glassy mass with many microcrystalline, small, light-coloured need-
les, with a low birefringence, forming, together with brown limonite,
dusty green chlorite and dark ore, a very dusty rock mass. Some larger
crystals of plagioclase, quartz, amphibole and epidote occur.

A. 443 (D. 17063) is a greenish fine-grained rock. Microscopically we
see a micro-crystal tuff with a large amount of small, clear fragments of
crystals, in amount prevailling over the crypto- to micro-crystalline basis.
The crystal fragments arc of andesine (twinned prisms), amphibole, more
or less calcified or chloritized, biotite and ore.

Another sample from A. 443 (D. 17064) is a tuffite with a calcareous

cement. Between rocks of this last mentioned type and limestones, carrying
volcanic material, all transitional rocks are found. Tuffaceous and micro-
conglomeratic limestones are micro- to fine-grained, grayish rocks. The
amount of inclusions is strongly varying, and also the dimensions of the
inclusions and conglomeratic material vary from small to rather coarse
grains.

In the conglomeratic limestones occur the following inclusions:
fragments of quartz-diorite, quartz-diorite-porphyrite, aplites, porphyrites
Tuff Formation, spilites, tuffs, vitric tuffs, schist material, and grains of
quartz, plagioclase, augite, amphibole and chlorite.

It is difficult to distinguish the tuffs of the Habana Formation and those
of the Tuff Formation. iVl. G. Rutten enumerated several distinguishing
features, which hold tme for the Southern facies of the Habana Formation
in Santa Clara Province. The most important one is the constant occurrence
of fragments of clear quartz crystals in the Habana Formation. Other dis-
tinguishing features are 1, the occurrence of clear twinned plagioclase in
the Habana Formation, 2, the occurrence of Upper Cretaceous fossils as
e.g. Orbitoids, Camerina dickersoni, Vaughanina cubensis, and Rudist frag-
ments, 3, the occurrence of detritical material of dioritic rocks. The second
one is a very good feature, because in very many samples fossils are found,
and the difference with other formations is evident.

The limestones of the Habana-Formation usually are yellow, sometimes
greenish or reddish, compact rocks with many fossils. They are thinbedded
to platy and sometimes occur in horizons of 15 meter width. Microscopically
we see crypto- to micro-crystalline limestones with patches of medium-
grained calcite and fossil material. Often they carry a few, small inclusions
of fragments of quartz, plagioclase or calcite.

The marls are white (at one locality purple) and compact. Often they
carry Smaller Foraminifera related to the Globigerinidae. The marls alternate
repeatedly with the limestones and microconglomeratic limestones.

At V. 79 (D. 16835) an almost totally silicified Habana limestone is
found. The rock is replaced by very small SiOg grains, and spheroidal
quartz. Some of the Foraminifera have saved their calcite, most of them
are silicified.

The rocks of the Habana Formation are formed on a submergent
bottom of a shallow sea. With regard to the thickness of the Haamp;na
Formation it must be mentioned that possibly large quantities of rocks
have been carried of by denudation, and the minimum thickness of
700 m found by us is not representative for the formation. R. H. Palmer
found a thickness of 7000 feet for this formation in the province of
Habana.

List of Fossils from the Habana formation.

? Archaias rutteni Palmernbsp;L. 128, A. 454.

Camerina dickersoni VAmetnbsp;M. 20, M. 62, M. 76, H;614,

L. 67, L. 128, L. 129, L. 130,'
L.136, L. 138, L.139, L. 435,
L.547, L.548, A. 62, A. 438,
A. 441,A. 457,A. 461,A. 466,
V.38, V.43, V.71, V.300,
V 307.

Catiierina sp. c.nbsp;L. 128.

Vaughanina cubensis Palmernbsp;M. 20, M. 62, M. 64, M. 65,

H.601, L.67, L. 136, L. 170,
L. 214, L.435, L.547, A. 436,
A.437,A. 441,A. 457, A.461,
V.36, V.37, V.38, V.43.

Orbitoides hrowni (Ellis)nbsp;M. 29, M. 62, M. 64, M. 76,

M. 101, L. 129, L. 136, L. 140,
L. 205, L. 225, L. 547, L. 548,
A. 62, A.436, A.437, A.438,
A. 466, V.36, V.43, V.71,
V. 300.

Orbitoides apiculata Schlumbergernbsp;M. 101, L. 136, L. 138, L. 225.

Orbitoides palmeri Gravellnbsp;M. 29, L. 128, L. 225.

Orbitoides sp.nbsp;M. 20, H. 601, L. 435.

Lepidorbitoides rutteni Thiadensnbsp;L. 128, L. 140.

Lepidorbitoides rutteni var. armata Thiadens L. 128.

Lepidorbitoides macgtllavryi Thiadensnbsp;L. 128, L. 140.

Lepidorbitoides palmeri Thiadensnbsp;L. 128.

Asterorbis sp.nbsp;M. 62, M. 101, L.67, V.36,

V.43, V.71.

Pseudorbitoides israelski Vaughan and Cole M. 62, M. 65, A. 457, A. 461,

V.36, V.37, V.43.

Pseudorbitoides trechmanni H. Douvillé H. 614, A. 436, A. 437.

Rudist fragmentsnbsp;M. 20, H.55, H.271, H. 274,

H.614, H.6I7, H. 621, L. 170,
L.205, A. 461, A. 466, V.38,
V.71, V.300, V.301.

Mitrocaprina tschoppi (Palmer)')nbsp;H. 616.

? Antillocaprina sp.nbsp;H. 627.

Barrettia sparcilirata Whitf.nbsp;L. 128, H. 627.

Parastroma sanche^ii H. Douvillénbsp;L. 549, L. 550, L. 553, L. 554.

Radiolites macroplicatus WhidF.nbsp;T. 1384.

dcterminavit H. J. Mao Gillavry.

Bournonia planasi Thiadens
Bournonia n.sp.
Bournonia sp

Biradiolifes aquitanicus Toucas
Tampsia rutteni Vermunt (in lit.)
Durania sp.

Titanosarcolites giganteus (Whitf.)

Hawhnsia cubae (Hawkins)^)
Lanieria lanieri Cotteau^)

Brissoides sp.

H. 241, H.245, L.225.
H. 601.
H. 206

H.624, L. 549.
H.614.
H. 260.

H. 245, H. 624, L. 128, L. 138,
A.450.
H. 233.

H.233, T. 1312, T. 1316,
T.1317, L. 130, L. 220.
T.1312.

Tertiary.

Upper-Eocene, Oligocene and Upper-Oligo-Miocene beds have been
found. Lithologically and in the field they are very much ahke and difficult
to distinguish. In the laboratory they could be separated by fossils, especially
by Foraminijera. For these reasons we have indicated on the map all the
Tertiary rocks with one colour, whilst E, EO, O and M indicate those
places, where we are sure of the special age of the rocks. There is a stricking
difference between the faunas of the rocks which are found on localities,
indicated with O and with M on the map, but it is not absolutely sure,
that the rocks considered as quot;Miocenequot; are not quot;Upper-Oligo-Miocenequot;.
On the places indicated with EO Upper Eocene Formanijera have been found
together with Oligocene ones (see page 47), and we are dealing therefore
with transitional beds. These faunas will be described in a separate study,
which is in press with the Journal of Paleontology and will appear in the
course of this year. The finding places of the different species are enumerated
in lists on page 46—47.

The Upper-Eocene rocks contain Discocyclina, Dictyoconus, Helico-
lepidina and Lepidocyclina {Isolepidina), the Oligocene ones Eulipidina and
Nephrolepidina-, the Upper Oligo-Miocene deposits contain Miogypsina,
Amphisorus and Archaias.

In Southern Santa Clara Province Tertiary rocks are found at many
places. The largest exposures are around Cienfuegos and North of Caracas;
moreover North-East of Trinidad and South and East of Sancti Spiritus.
The two first mentioned regions are in connection with the large basin of
Colon, the last two with the basin of Moron. Moreover, Tertiary strata arc
found North and South of Manacal in two small synclines on the schists.

Around Cabaiguan folded Tertiary beds are found unconformably
over rocks of the Habana Formation. At L. 104 SE of Cruces, finally, a
small Tertiary outcrop has been found. These last mentioned Tertiary rocks

0 determinavit J. van Soest.

may be synclinal or surrounded by faults. The Tertiary beds are transgres-
sive over all the older Formations, as can be seen on the map. Stratigraphi-
cally a large disconformity between the Upper Cretaceous and Upper
Eocene must exist, since Lower and Middle Eocene rocks never have been
found. A structural unconformity is found also between the Habana beds
and the Upper Eocene beds, although not on all places, where they border
with each other. This structural unconformity is exposed around Cabai-
guan, where the Upper Cretaceous strata are folded with a general East-
West strike, and the Tertiary beds are folded in a more gentle way, striking
NW—SE. Moreover North of San Juan a structural unconformity between
both formations has been found as can be seen on the map of Ai. G. Rutten.
In the large exposures of Tertiary and Upper Cretaceous rocks around the
bay of Cienfuegos no structural unconformity could be observed, although
we found the Tertiary overlapping the Habana Formation. As it was difficult
to distinguish the rocks of both Formations in this region, only fossils were
decisive.

The Tertiary is transgressive over the diorites South of Gavilan and
Sancti Spiritus and North of Manacal; over the Tuff-Formation North
of Cienfuegos, South-East of Cruces, East of Cruces and South of Sancti
Spiritus; over the schists North of Trinidad and near Manacal. Pebbles of
all these formations are found in Tertiary conglomeratic limestones.

On the whole in the Southern part of the Province the Tertiary is
gently folded. Only North of Cabaiguan some steep dips up to 50° were
found. No inter-tertiaiy unconformity has been observed. On other places
on the island, e.g. in Pinar del Rio a distinct unconformity between Eocene
and Oligocene on the one side and the Upper-Oligo-Miocene on the other
side is found. Palmer (32) too, mentions this inter-tertiary structural
unconformity. The Upper-Oligo-Mioccne beds in our district are found on
three places. At L. 232 opposite to Cienfuegos, right across the bay, the
Upper-Oligo-Miocene beds are horizontal, while the Eo- and Oligocene
iDcds 2 km North of Cienfuegos dip up to 30°. Here, probably, we find
indications for a structural unconformity. At M. 591 and Al. 595 on the
Carretera Central near Jatibonico the Uppcr-Oligo-Aliocene beds dip only
very little (about 5°), while the Eo-Oligocene beds dip slightly more. Here,
however, no indications for the structural unconformity are present.

The Tertiary beds are mainly composed of white marls and white-
yellow, thin bedded limestones, moreover of conglomeratic and fine sandy
limestones. At one locality a limy, sandy shale, rich in coal has been found.
N. of Cabaiguan the Upper-Eocene rocks begin with a medium-grained
basis conglomeratic L. 43! (D. 16551, D. 16552).

The marls are sterile or carry many smaller Foraminifera, which could
not be isolated and in consequence could not be determined. They carry
small grains of quartz, chlorite and plagioclasc.

The limestones are white or yellow, mostly thin-bedded, sometimes
thickbcddcd. They are sometimes sterile, but mostly carry many organisms.

Fine-grained to marly limestones with Globigerinidae and fine- to medium-
grained Orbitoidal-limestones are common in the district. These rocks, too,
enclose volcanic material, which mostly is detritical and sometimes tuffaceous.

The conglomeratic limestones carry many inclusions, measuring mainly
I—1 cm in diameter, sometimes more. The samples of L. 431 (D. 16551,
D. 16552) e.g.: fragments of quartz-epidote-schist, porphyrites with chloriti-
zed groundmass or phenocrysts, quartz-diorites, quartz-grains, plagioclases
(albite to labradorite, myrmekite), microcline, amphibole, biotite, garnet,
chlorite a.s.o.

The amount of calcite cement and rock fragments is strongly varying,
mostly the calcite is predominant. In some cases we found in the limestones
well rounded porphyrite fragments (detritical material) at the side of polyan-
gular crystal fragments of quartz or plagioclase. The latter probably are of
tuffaceous origin and represent uncertain traces of Tertiary volcanic activity.
As already mentioned, all these rocks are distinguished from those of the
Habana-Formation by fossils only.

One Tertiary, limy, sandy shale, rich in coal is a remarkable rock. It has
been found at L. 433 (D. 16554) lying almost horizontally over conformable
white marls. The rock is dark, greasy, slate-like, with a black streak. Micros-
copically we see a finely bedded, dense aggregate of quartz and calcite grains,
muscovite scales, and black coal powder.

In the Upper-Eocene the limestones and conglomeratic limestones are
predominant, while in the Oligocene white marls prevail. The Oligo-Miocene
beds which probably can be parallellized with the quot;Guines-limestonesquot;,
are composed of conglomeratic to sandy marls.

Fossils from Upper Eocene beds:

Dictyoconus fontabellensis (Vaughan)nbsp;M. 33, M. 59, M. 664, M. 671,

L.216, L.431, L.556, A. 481,
A. 483, V.75, V.306, V. 362,
V.371.

Camerina petri M. Ruttennbsp;V 17.

Camerina malberti M. Ruttennbsp;V. 18, M. 664.

Caf?ierina sp. cf. C. parvula Cushman M. 678.
Camerina sp. d. Thiadensnbsp;M. 678.

Camerina sp. (is Amphistegina cubensis

Palmer, pars)nbsp;M. 33, L. 119, A. 481.

Operculina sp.nbsp;M. 664, H. 281.

LepidocycUna mortoni Cushmannbsp;M. 678, M. 681, V. 17, V. 18.

LepidocycUna pustulosa H. Douvillénbsp;M. 681.

LepidocycUna trinitatis H. Douvillénbsp;V. 17.

Helicolepidina spiralis Toblernbsp;M. 678, M. 681, V. 17.

Discocyclina hlumenthali Gorter and v. d.
Vlerknbsp;M. 678.

Discocjclina cubensis Cushmannbsp;V. 18.

Discocjclina vermunti M. G. Ruttennbsp;M. 664, M. 678, M. 681, V. 17

Discocjclina sp.nbsp;M. 33, M. 59, M. 664, M. 67 ^

H. 281, H.285, L. 104, L. 163,
L.216, L.431, L.556, A. 481,
A.482, A.483, V. 16b, V. 18,
V.306, V.362, V.371.

Fossils of the transitional beds between Upper Eocene and Oligocene:

Lepidocjclina maracaibensis Hodsonnbsp;L. 588.

Lepidocjclina mortoni Cushmannbsp;L. 588, L. 590.

Lepidocjclina supera (Conrad)nbsp;L. 588.

Lepidocjclina tschoppi Thiadensnbsp;L. 588.

Lepidocjclina weehi Hodsonnbsp;L. 588.

Lepidocjclina formsa Schlumbergernbsp;L. 588, L. 590.

Helicolepidina spiralis Toblernbsp;L. 588.

Fossils of Oligocene beds:

Camerina sp. A.nbsp;L. 229.

Camerina sp. B.nbsp;L. 229, H. 4, H. 10.

Planularia sp.nbsp;L. 229.

Lepidocjclina formosa Schlumbergernbsp;L. 229, H. 25, M. 587, M. 596.

Lepidocjclina undosa Cushmannbsp;L. 229.

Lepidocjclina marginata (Michelotti)nbsp;L. 229.

Lepidocjclina petri Thiadensnbsp;M. 587.

Fossils of Oligo-Miocene beds:

Archaias adunca (Fichtel and Moll)nbsp;L. 232, M. 591, M. 595.

Awphisorus matlej Vaughannbsp;M. 591, M. 595.

Miogjpsina hawkinsi Hodsonnbsp;L. 232, M. 595.

Moreover, in the Ternary beds many Smaller Foraminifera, Radiolaria,
Corals, Lamellibranchiata, Gastropoda and Echinids arc found. As in most of
the cases it was possible to determine the age with the Larger Foraminifera,
the detcrminadon of the other fossils would be of palaeontological interest
only. This has not yet been done for two reasons: first because time was
lacking and secondly becanse part of the matenal was rather bad.

Chapter III: TECTONICS.

When we consider the tectonical features of the Southern part of Santa
Clara Province, first of all the tectonics of the Schist-Formation must be
treated. There are two possible suppositions.

1.nbsp;The Schist-Formation is an autochthonous complex.

2,nbsp;The Schist-Formation as a whole is part of an overthrust mass.

First we will treat the second possibility. The distribution of the dioritic
rocks W., N. and E. of the Schist-Formation especially induced us to consider
this. In this case the schistcomplex would be an overthrust mass with no
known root, coming from the South and lying on the diorite-bathoHth.
During the overthrusting already the schist must have been crystalline. The
orogenic movement was pre-Maestrichtian, as in the rocks of the Habana-
Formation detritical material of schists is found. With this supposition the
following observations probably might easily be explained. 1. the distribu-
tion of the diorite around the schist-complex. 2. the very large thickness of
the Schist-Formation, which might be only apparent, in consequence of the
existence of a folded pile of quot;nappesquot; above each other. 3. the lack of evident
contact-metamorphic phenomena in the schists. 4. the existence of vertical
and overturned schists on the Northern boundery. 5. the cataclasis in the
diorites, especially on the Southern side near the boundery with the schists.
6. the lack of detritical schist material in the Tuff Formation. 7. the straight
boundary between the schists and the diorites on the Northern side of the
schists.

The cupola-like form of the schist-complex need not be an objection
against this supposition, as it might have been causcd by pitching of the
axis of the overthrust masses to the W. and thé E.

There are, however, some decisive objections against the above treated
supposition. We see that the front of the supposed quot;nappequot; lies upon the
diorites on the North side and that the flank of the quot;nappequot; dips below
the same diorite at the W. side. This is tectonically impossible.

A second objection is the occurence of dioritic rocks within the schists,
(probably these are dikes in the schists, although one might consider them
as quot;inlierquot;) together with the hydrothermal rocks at the Mina Carlotta at
M. 254, which almost surely came into being by the hydrothermal action of
the Dioritic Intrusion (no volcanic activity capable for hydrothermal action
on so large a scale being known after the Dioritic Intrusion).

A third objection is the consideration that it is almost impossible that
during the enormous orogenic activity, wanted for the movement of the
supposed overthrust masses, the rocks of the Tuff-Formation, which at

that time already existed, only should have been affected by an orogenic
activity of medium intensity.

The other possibihty is that the schists are autochthonous. All the
objections against the quot;nappequot; are, on the other hand, arguments in support
of this last supposition. In this conception the schist emerged during the
Upper-Cretaceous orogenesis and are separated to the North side from the
diorites by a large straight fault. The lack of contact-metamorphic pheno-
mena and the steep and overturned position of the schists on the Northern
side are probably explained by this fault.

The thickness of the Schist Formation, being almost 12000 m. is not
a decisive objection against this supposition. The orogenetic activity which
after the consolidation of the diorites caused the cataclastic phenomena,
very probably also formed the fault. Decisive objections against the second'
supposition cannot be indicated, and we are inclmed to adopt this conception
as the most probable one, being at the same time the most simple one. The
distribution of the diorites around the schists remains a remarkable fact.
Maybe the large schist dome impeded the dioritic magma to form a regular
batholith and the magma followed the discordance-plane between the
schists and the tuffs.

There are four different phases of orogenesis known in Southern
Santa Qara: the first one during the Upper Cretaceous, before the
deposition of the Habana Formation; the second one in Lower- and
Middle Eocene time, before the sedimentation of the Upper Eocene; the
third one during the Ohgocene, before the uppermost Oligo-Miocene
time; and the fourth one ^ter Oligo-Miocene time.

The Upper-Cretaceous orogenesis must have been rather strong.
Probably the schists have emerged during this orogenesis because almost
no fragments of schists have been found in the Tuff-Formation. The strong
cataclasis of the already consolidated dioritic rocks came into being during
this orogenetic phase, as the younger movements were rather unimportant.
Moreover the fault between the diorites and the schists very probably was
formed equally during this orogenesis. The structural unconformity between
the Habana-Formation and the Tuff-Formation is rather great as can be seen
on the map all around Cienfuegos and Fomento. Moreover it is proved by
the occurrence of detritical material of the older formations in the conglo-
meratic limestones of the Habana-Formation.

The Upper Cretaceous movement in this part of the island appears to
have come from the South, because of the vertical and overturned position
of the schist in the Northern side of the complex, and the trend in the cata-
clastic dioritic rocks.

The second phase of orogenetic activity had a varying intensity at
different localities. The rocks of the Habana-Formation in the S\V. part
of the Province are gently folded and almost conformable with the Tertiary.
No evident structural unconformity between the Habana-Formation and
the Tertiary is observed here. The Tertiary overlaps in this part of the Pro-

vince the Habana-Formation. In the North-Eastern part of our district the
Lower and Middle Eocene orogenesis has been much stronger, as can be
seen from the structural unconformity between Habana-Formation and
Tertiary in the region around Cabaiguan, and also by the rather steep dips
of the Habana Formation. The direction of the Lower or Middle Eocene
movement probably is equally from S to N according to the overturned
Habana beds near Fomento and near Guayos (Carretera Central).

The Oligocene orogenesis in the district had a gentle character, as can
be seen from the low dips of the Tertiary rocks in the district throughout.
Only in the neighbourhood of Cabaiguan, again, some steeper dips are
found, witnessing that to the Northern and Eastern side of the district also
this orogenesis became stronger.

The fourth orogenesis is proved by the very gently dipping Oligo-
Miocene beds exposed on the Carretera Central W. of Jatibonico over a
rather large distance. This orogenesis must have been very gentle, as the
same Oligo-Miocene beds have horizontal position at L. 232 SW. from
Cienfuegos. As these beds are the youngest ones, surveyed by us, we are not
sure about the uppermost limit of the age of this orogenesis. The direction
of the movement of the two youngest orogeneses is not known in our
district as the folds are only very gentle and by no means indicate a special
direction of the dynamic forces.nbsp;:

Chapter IV: PETROLOGICAL NOTES.

Chemical analyses were made of five rocks from Southern Santa
Clara Province, by Mr. W. van Tongeren. The results of these analvses are
given here in two lists, together with the Niggli values and the number
of the section in the Niggli tetraeder.

1.nbsp;Diorite aplite, M. 210, 2 km. S. from Manicaragua.

2.nbsp;Quartz-hornblende-biotite-diorite. M. 322, Rio Arimao, 1 km. NNW
from Manicaragua.

3.nbsp;Amphibolite from the Diorite Intrusion. M. 255, 8 km. S. from Mani-
caragua.

4.nbsp;Porphyrite Tuff Formation, L. 45, 2 km. N. from Hormiguero.

5.nbsp;Quartzfree-pyroxene-hooibergite. L. 302, 4|- km. S. from La Moza.

Table I (Weight percent.)

Table IL (Niggli values.)

I computed the Niggli values of these rocks together with those of the
analyses pubhshed by H. M. E. Schurmann (45) and M. G. Rutten (41)
in a Niggli diagram. This diagram is the same as that of M. G. Rutten
(41) as the 5 new analyses of Southern Santa Clara fit well into the latter.
So it seemed unnecessary to reprint this diagram. The quartz-hornblende-
biotite-diorite is representative for the large intrusion. With the integration
stage this rock appeared to consist of 64.1 % felspar, 16.3 % hornblende,
11.2 % quartz, 5.3 % biotite, and 3.1 % ore. The composition of this rock
agrees with the normal dioritic magma of Niggli. It has a slightly more
basic character than the quartz-diorites of Schurmann, which belong to
the grano-dioritic magma. The diorite of M. G. Rutten is much more
acid. This is not astonishing, as it is found in smaller intrusions in the
serpentines and may be a younger acid differentiation of the quartz-dioritic
magma.

Also analyses were made of extreme acid and basic differentiations
of the batholith, a diorite aphte and a quartz-free pyroxene-hooibergite.
The large MgO content of the latter is remarkable.

Of one amphibolite an analysis was made in order to state its origin.
From the results of the analysis it may be deducted that this amphibolite is
an orthorock. The chemical composition shows some resemblance with
that of analysis 5 of Schurmann of a gabbroidic rock out of the serpen-
tine in Santa Clara. The content of alkahes, however is different.

Finally a porphyrite from the Tuff Formation was analysed. The basic
character of this rock is remarkable.

As we have seen in the pétrographie descriptions in this paper, various
thick beds of Meso-Cretaceous volcanic rocks are found, while in Upper-
Cretaceous time in North Santa Clara a large serpentine massive and in South
Santa Clara a large quartz-dioritic intrusion have been formed. The quartz-

diorite is younger than the serpentines as dikes of the former are found in
the latter (41 p. 18). The difference in age, however, is only small, both
being post-Turonian-Emscher and pre-Maastrichtian. So we have Middle
Cretaceous tuffs, porphyrites, diabases and spilites and Upper-Cretaceous
serpentines and diorites close together. Although the geological and
chemical data of these rocks are still unsufïîcient it seems well to make
some suggestions about the possible relations. The serpentines and quartz-
diorites are very likely differentiation products of some primary magma.
There are several possible relations.

1.nbsp;The rocks belong to three different magmas.

2.nbsp;There are two more or less indépendant magmas, a Middle-Cretaceous
one and a Upper-Cretaceous one.

3.nbsp;Only one magma produced by differentiation all the different rocks.

ad. 1. If the rocks belong to different magmas, nothing can be said
about petrological relations inter se. This, however, seems rather improbable,
as the rocks are found close to each other and even together, as the age of
at least the serpentines and diorites differs only slightly, and as in chemical
and partly in mineralogical features they show likeness, as can be seen from
the analyses and the Niggli-diagram.

Moreover, if the serpentines and quartz-diorites belong to different
magmas, then the other differentiates of the two presumed cycles must be
somewhere and it would be astonishing that no traces of them are found.

ad. 2. The second possibility is that of two magmas. In this case nothing
can be said about the Middle-Cretaceous one, as only extrusive rocks arc
known. If the serpentines and diorites arc differentiation products of one
primary magma, which is not improbable, according to their distribution
and age, then this differentiation must have been a gravitative one. The
peridotite, from which the serpentine originates, came into being below
a dioritic rest-magma. However, the serpentines are found at the surface
in the Northern part of the Province and are cut by dioritic veins. This
probably can be explained by deep-seated tectonical activity during or
shortly after the consohdation of the peridotite, and before'the Dioritic
Intrusion. Schurmann already drew attention to the possibility of tectonical
influences on the surface distribution of serpentines and diorites in Cuba.
Moreover the complicated tcctonical features, described by M. G. Rutten
for the serpentines, support this possibility.

The question arises whether it is possible to find the chemical composi-
tion of the primary magma. Some general considerations prove that it is
not yet possible to solve this question. Primary we do not know anything
about the quantities of serpentines, diorites and gabbros formed during the
differentiation. Moreover in the rocks sampled and described by us, no one
occurs which represents in chemical composition the original primary magma

ad. 3. The third possibiHty is that of one magma. The mineralogical
likeness of the rocks of the Tuff-Formation and the Dioritic Intrusion
together with the NiggU-diagram seems to support this supposition. On
the other hand the extrusive rocks are the eldest ones, while one should
expect the extrusive period of a cycle to be the youngest one.

Chapter V: SURVEYED COURSES.

In this chapter only some surveyed courses are chosen for a detailed
description. I choose those courses which are characteristic for some impor-
tant geological phenomena.

I. Rio Calabazas-Cabaiguan-Guayos-Sancti Spiritus-Jatibonico. The Rio
Calabazas crosses the Carretera Central at km. 354,4. Here we find structure-
less tuffs of the Tuff-Formation, which continue about 2 km. At km. 358,1
occurs an altered silicified porphyrite (L. 430, D. 16549), while from km.
358,7 to km. 361 well bedded tuffs dip to the East about 50°, striking N 190 E.
At km. 363 again structureless tuffs are found and at km. 364 the last tuff
outcrop occurs. Then we pass into rocks of Tertiary age and at km. 364,7
we find limestones, conglomeratic limestones and marls. The boundary
between the two formations is about near km. 364,4. The Tertiary rocks
are folded dipping up to 40°. At one locality a dip of 50° was found. The
mean dip, however, is 35—40° S.; the strike is NW—SE. The Upper-Eocene
beds begin with a medium-grained basis conglomerate (L.431, D. 16551,
D. 16552) with fragments of Dictjocomsfontabellensis (Vaughan), Discocyclina
sp., Camerina sp., many Smaller Foraminifera which we could not isolate
nor determine, and with many rounded fragments of foreign rocks as e.g.
of quartz-biotite-diorite, quartz-diorite-porphyrite, porphyrite from the
Tuff-Formation, quartz-epidote-chlorite-schists, and fragments of quartz and
plagioclase and other crystals. The average diameter of the pebbles is
cm. Upon this conglomeratical limestone lie conformably light coloured
limestomes, and white to greyish marls. In Cabaiguan the same marls\re
found and at km. 369, direct S. of Cabaiguan black, coaly shales are found,
together with greyish green sandstones, concordant upon these marls. Here
the rocks dip slightly to SW. or lie almost horizontally; we are in the core of
the Tertiary synclinal. The coaly shales arc a finely bedded, dense aggregate
of quartz and calcite grains, muscovite scales and a fine coaly powder. The
sandstones are built mainly of schist material, undulose quartz, muscovitc
and some plagioclascs, derived probably from the diorites. Moreover, some
Smaller Foraminifera, probably Globigerinidae, arc found in them.

West of the Carretara Central at L. 546 we find the same Tertiary rocks
as at L. 431. Between L. 546 and L. 547 no good rock-exposures are found,
while at L. 547 Orbitoides-\\mz%x.onz% of the Habana Formation, carrying
Orbitoides browni, Vaughanina cubensis and Camerina dickersoni arc found.
More to the West from this road we find many large, well rounded blocks
of rocks of the Tuff-Formation, indicating that we arc approaching the
boundary between the Tuff Formation and the Flabana Formation. At
L. 549 and the following localities many large specimens of Parastroma

sanche^i have been found. The rudist hmestones alternate with marls and
coarse red limy conglomerates. The rocks of the Habana Formation are
gently folded, dipping 20—25° SSE. Direct North of the road we find rocks
of the Tuff-Formation. From L. 551 going Southward we first meet loose
rudists in the field, then sometimes white marls and conglomeratical hme-
stones (N8oE 25 S.). Without any change in the landscape we pass the
boundary with the Tertiary rocks and at L. 556 we find a light yellow hme-
stone with Dictyoconus fontabellensis and Discocyclina sp. striking NW—SE
with a dip of about 5°. Until Cabaiguan marls and limestones are rather
badly exposed. In Guayos (Car. Centr.) we pass into the Habana Formation.
At km. 374, 2 the marls and limy sandstones dip 20° N striking N 100 E. So,
here we see a difference in tectonic arrangement of the Tertiary and Upper-
Cretaceous rocks. This difference is emphasized by the exposures 2 km. S.
of Guayos. Here we find a E—W running chain of hiUs, consisting of con-
glomeratic limestones and white and greyish marls, which are strongly
folded. Going from N to S we find on a distance of 1500 m. the following
dips: 70° N, 90°, 60° S, 50° S, 25° N, 70° N, and 70° N.

At L. 435 we find strongly folded Orbitoides-Vimtstonamp;s, with Orbitoides
sp., Vaughanina cubensis, and Camerina dickersoni. East of the Carretera
Central the same rocks and rudist hmestones occur. At V. 306 a conglome-
ratic limestone with Dictyoconus fontabellensis and Discocyclina sp. is found
in a synchne on the Habana beds. At V. 307 the rocks of the Habana Forma-
tion with Camerina dickersoni are shghtly overturned, dipping strongly to
the S. At km. 377,2, 200 meter South of L. 435 on the Carretera Central
the steep North dipping Habana Formation-rocks overlie porphyrites and
red and green tuffs of the Tuff-Formation, striking probably N 40 E,
dipping 50 W. These rocks show amphibohtization of the augites, being
shghtly affected by contact metamorphosis, caused by the Dioritic Intrusion.

Near the Rio Tuinucu we pass into dioritic rocks. First we find about
4 km. decomposed sandy diorites. Then at L. 437 dark schistose rocks with
dark and light veins are found. The hght veins are the youngest. The dark
schistose rocks are amphibolites of unknown origin, built mainly of green
pleochroitic hornblende, clear albite and oligoclase grains, and green biotite
streaks. The light dikes are plagiaplites with microgranophyric intergrowth-
structures. At L. 438 the same rocks occur together with pyroxene-amphi-
bolites and amphibolites with a rehc porphyritic texture. Some hundred
meters S. of L. 438 again the normal diorites, more or less decomposed
into sandy diorites, are found, continuing as far as km. 388, 1 km. E. of
Sancti Spiritus. At M. 582 we find tuff, which by contact metamorphosis
has been urahtized and epidotized (D. 16753). M. 582bl (D. 16755) is a
metamorphic tuffbreccia or porphyrite, as we find altered rock fragments
and phenocrysts of augite imbedded in a medium grained aggregate of
epidote, zoisite and augite crystals. This last aggregate probably is altered
tuff material or porphyrite groundmass. Together with this rock calcite-
quartz-garnet-rocks, garnet-rocks and a marble are found. At M. 583 coarser

grained garnet-rocks occur (plate, figure 3) in a small hillock 50—100 meter
North of the Carretera Central at km. 389. At km. 389,4 white marls and
micro-conglomerates of the transgressive Habana Formation are found,
thoroughly folded, dipping 45° to the NE. Imperceptibly they grade into
Tertiary rocks; white cavernous marls .without clear bedding. Upper-Eocene
fossils are not found here. At M. 587 (km. 392,7) in a large quarry many
fossils are found, Lepidocyclina formosa, Lepidocyclina petri, and many other
Foraminifera, corals, Lamellibranchiata, Gastropoda etc. From M. 587 to
Jatibonico white mads are found carrying Lepidocyclinae, Oysters, Pectinidae
a.s.o., often covered by alluvial detritus, containing much schist material.
At M. 591 and M. 595 Archaias adunca, Amphisorus matleyi and Miog ypsina
hawhnsi occur in gentie dipping layers. Here the Upper-Oligo-Miocene beds
proof the existence of a small post-Upper-Oligo-Miocene orogenesis.

N. of Jatibonico we find the Upper Eocene and Oligocene beds and
transitional beds between these two indicated by the occurrence of Heli-
colepidina spiralis and Lepidocyclina mortoni together with lepidocyclina {Eulepi-
dina) formosa. Still more to the North the rocks of the Habana Formation
are found.

II. Baez-Fomento-Manacal-Trinidad (see also section I).

From Baez to L. 515 we pass through the Tuff Formation. Green
bedded tuffs, structureless tuffs and porphyrites, the latter forming small
hills, are found. The main strike is N90E, dipping 60—90°N. 5 km. S.from
Baez a hill formed by Provincial limestone lies 1 km. \V. from the road.
Near L. 517 the high way passes a zone of Provincial limestones with
Caprinids {Coalcomana ramosa and a Monopleurid). Several banks of lime-
stones alternate with tuff-breccias. At L.5I5 a Radiolaria tuffite occurs.
At L. 514 we find a basis-conglomerate of the Habana Formation,
containing small and large pebbles (up to 10 cm.) of tuffs, porphyrites.
Provincial limestones with many smaller Foraminifera.

From L. 514, through Fomento untill 2 km. S. of Fomento rocks of
the Habana Formation are found; limestones, maris, conglomeratical lime-
stones etc. 1 km. NE. from Fomento at H. 601 (the same place as H. 627)
a very rich fauna is found in the limestones. Archaias rutteni (Palmer),
Camerina dickersoni Palmer, Camerina sp. c. Thiadens, Orbitoides palmeri
Gravell, Lepidorbitoides rutteni Thiadens and some other species of Lepidor-
bitoides, Barrettia sparcilirata Whitf., Bournonia n. sp. Thiadens, Bournonia sp.
and Antillocaprina moreover many Corals, Oysters and Echinids. Around
Fomento the Habana Formation lies in a synclinal upon the Tuff Formation.
The synclinal is overturned toward the N. and NE. side, the Southern wing
dipping 40° toward the Tuff Formation. The latter begins with a coarse
spilite-porphyrite-breccia, at L. 572 (D. 16609). From Fomento to Trinidad
the railroad has been followed. The rocks of the Tuff Formation here are
tuffs, porphyrites and intercalated thinbedded Provincial limestones. The
outcrops of the latter are too small to be drawn on the map. Near km. 42

(2,6 km. S. of L. 572) the first dioritic rocks are found: strongly weathered
porphyrites with apHtic dikes. 4 km. S. of L. 572 we find quartz-diorite
in the general decomposed sandy habit. This keeps going on 3,7 km. Then
again darker green amphiboUtic rocks are found, alternating with normal
diorites. At L. 570 a pyroxene-amphibolite and a amphibohte occur, while
at L. 569 a cataclastic vindite has been sampled.

200 m. S. of L. 569 and furtheron at L. 567 and L. 566 strongly weathered
quartz-bearing marbles, calcite-quartz-muscovite-schists and crystalline lime-
stones are found, striking N 40—60 E. dipping 60—90° S. No traces of
contact metamorphism are observed. At our right hand we look down into
the dioritic landscape. 750 m. East of L. 564 we are in the diorites again.
Very curious are the strongly weathered porphyrites sampled at L. 564. The
groundmass of this rock carries a considerable amount of magnetite and
chlorite, and is very much ahke the groundmass of the porphyrites of the
Tuff Formation. If this rock really is a porphyrite of the Tuff Formation, it
must be considered as an inclusion in the diorites, and it is curious that it
is only so little altered.

From L. 563 to 200 m. N. of M. 664 rocks of the Schist Formation are
found as e.g. crystalline limestones, and green chlorite schists; moreover:
young schists breccias. The rocks of the Schist Formation here form a small
anticline.

At M. 564 Tertiary rocks He unconformably upon the schists. We find
limestones and microconglomeratic limestones, containing much schist
material and also pebbles of porphyrite. Many Lepidocjclinae, Discocyclinae
and Dictjoconus fontabellensis indicate the Upper Eocene age. First they dip
gently South, then they are found in horizontal beds and at M. 667 they dip
50° N. over diorites, which outcrop here on the border of the transgressive
Upper Eocene and the schists. At km. 48, 400 m. N. of Manacal, the schists
•lie probably horizontally. In Manacal gently South dipping serpentine-
schists occur. (D. 16775). 600 m. E. of Manacal hght and dark marbles are
found. At M. 671 again Upper Eocene conglomeratic limestones are found
with Dictjoconus fontabellensis and DiscocjcUna sp. 400 m. S. of M. 671 schists
and schists-breccias are found, lying horizontally or dipping slightly South.
Passing the Rio Agabama we still find schist-breccias. At M. 678 we are
definitely in the transgressive Tertiary beds. Limestones, marls and conglo-
meratic limestones are found carrying Cat?ierina sp. cf. C. parvula, Lepidocj-
clina mortoni, L. pustulosa, L. sp. Helicolepidina spiralis, DiscocjcUna blumenthali,
D. vermunti. From M. 678 to Trinidad Tertiary rocks keep going; we are
are not certain, to which part of the Tertiary they belong as only few small
samples were collected.

III. Course from L. 330 S. of Provincial via Manicaragua to M. 269 S. of

Manicaragua (about section III).

From L. 330 to L. 327 covering a distance of 2150 m. we found the

following section.

L. 330 0—300 m. blue and beige, rather fine grained limestones with

needles of Spongta (D. 16533), and Radiolaria
(D. 16532), alternating with tuffs. At the end of
the 300 m. tuff-porphyrite-breccias (D. 16531) dip
60° N.

L. 329 300—350 m. Limestones.

350—450 m. alternating crystall-tuffs and vitric tuffs (D. 16530,
D. 16529).

450—550 m. blue limestones E.—W. 50° N. in beds of 10 cm.
thickness.

L. 328 550nbsp;Limestones N. 90 E., 30—50° N.

550—750 m. no exposures.
750nbsp;Limestones with Caprinids.

750—950 m. no exposures.
950—970 m. Limestones and Caprinids.
970—1100 No exposures.
1100—1200 Limestones with Caprinids.
1200—1400 m. Depression.
1400—1500 m. Limestones with Caprinids.
L. 327 1500—1850 m. Limestones with smaller Foraminifera QGlobigerina)

Radiolaria (D. 16562) and marls. N70E, 30°, N.
Conglomeratic limestones (D. 16522) Gray and blue,
rather crystalline limestones N95E, 55° N. and
marls.

1850—2150 m. Tuff-breccias.

The Rudistids and Caprinids arc }Tepejacia corrugata Palmer and
Caprinuloidea sp. which, by comparison with Mexican forms, indicate a
Cenomanian-Turonian age.

The limestones are fine-to medium-grained, microconglomeratic rocks,
cut by many calcite veins.

Going Southward the road descends into a plain, formed by tuffs,
porphyrites and tuff-porphyrite-breccias. The breccias are structureless. At
L. 325 a ?dike of a silicificd prehnite rock is found. This is a hydrothermal
rock of unknown origin, probably it is the first trace of the approaching
diorite contact. In the tuff landscape the coarse tuff-porphyrite-brcccias
form small ridges with tuff depressions between them. At L. 323 (D. 16518)
and L. 322 (D. 16517) and 450 m. S. of L. 322 we still find rocks, typical for
the Tuff Formation. At L. 320 (D. 16516) an altered porphyrite with rests
of quartz phenocrysts is found, while the rocks of L. 319, originally probably
belonging to the Tuff Formation (tuff breccias and porphyrites) are silicificd
and altered by the contact of the diorite rocks. A weathered quartz-diorite-
porphyrite is found at L.318 (D. 16512) at the side of a quartz-chloritc-
epidote-rock (D. 16513), which probably is an altered porphyrite. At L. 317
a Pquartz-amphibole-diorite-porphyrite has been found, while at L. 316 a

silicified chloritized spilite occurs. At L. 315 we found sandy soil, which is
typical decomposed quartz-diorite. This continues until Manicaragua.
Near the tuff boundary light-coloured dikes of quartz-diorite-porphyrite
occur (L.315, D. 16508, D. 16509; L.313, D. 16505; V. 123, D. 16857,
D. 16858; V. 122, D. 16855, D. 16856; V. 119, D. 16852), while at L. 314
(D. 16506), V. 124 (D. 16859), V. 125 (D. 16860) and V. 118 (D. 16850)
quartz-diabases are found. The diorites found here are more or less decom-
posed, forming deep gulhes in the landscape.

From Manicaragua going Southward first we remain in the same
dioritic rocks. At M. 195 a silicified spilite is found as inclusion in the diorite
(D. 16685). At M. 198 a cataclastic granodiorite aphte has been sampled.
200 m. Southward the colour of the soil becomes darker brown and we find
in the field many blocks of schistose rocks. Very probably these rocks are
gneissic dioritic rocks. No samples were taken. 350 m. N. of M. 203 again
light coloured weathered diorite-soil occurs, while from M. 203 to M. 205
diorites are found. In the diorite of M. 203 the plagioclases are strongly
replaced by sericite and calcite. They have been, like the rocks of M. 205,
affected by cataclasis. At M. 206 we found green, strongly weathered schis-
tose rocks, which are probably gneissic rocks of dioritic composition,
carrying dark inclusions of calcite-chlorite schists of unknown origin
(D. 16690), possibly derived from the Schist Formation. All the rocks are
cut by light, strongly weathered dikes of mylonitized aplites (D. 16691).

From the point 120 meter S. of M. 206 to M. 214 again more or less
weathered diorite is found, cut by light aplitic and lamprophyric dikes.
A chemical analysis was made of the plagiaplite of M. 210 (analysis no. 1).
From M. 214 to a point 300 m. South of M. 218 we find strongly
weathered schistose rocks, and at M. 217 and M. 219 meta-hooibergites
(D. 16695, D. 16696). Here, again, we consider the schistose rocks as myloni-
tized dioritic rocks, which are found together with altered hooibergite. More
Southward again typical quartz-diorite-sand is found in a small vaUey. At
M. 225 epidote-amphibolites of unknown origin (D. 16698) and gneissic
diorites (D. 16699) are found, strongly cut by granodiorite-aplite-dikes
which have been mylonitized. One broad dike, measuring 15 meter in
diameter is found. From M. 225 to M. 229 the same dark schistose mylo-
nitized rocks occur. At M. 230 and M. 233 gneissic diorites were sampled,
while at M. 255 an amphibolite occurs (analysis no. 3). From M. 255 to
M. 260 weathered and badly exposed schistose amphibolitic rocks arc
found; ± NIOOE, 60—90° S. 100 m. South from M. 260 the first mica-
schists are found. They are strongly weathered. At M, 263 quartz-bearing
marble occurs. From M. 265 to M. 269 we find in a narrow valley thinbedded
blue limestones ^ N120E dipping steeply South or standing vertically.
Near M. 269 the first North dip is found.

Chapter VI: PREVIOUS LITERATURE.

A rather large amount of literature concerning Cuban geology exists.
Notwithstanding, the geologic knowledge of the island in general and
also of the Southern Santa Clara Province is very poor.

With the aid of Prof. Rutten, who kindly put at my disposition his
bibliographic notes on papers concerning Cuban geology, I was able to
compile a rather large list of papers and books concerning Southern Santa
Clara Province. Not all numbers could be consulted quot;in originalequot; as many
of them are not to be found in any library in Holland. Most papers are
treating ore deposits or palaeontological subjects. Only two geological
maps of the island exist, that of Castro and Salterain which is reprinted
with slight alterations in the report of Hayes c.s. (20), and in the book of
Hill (21), and that of Lewis (23) which is repnnted in Schucherts book
(44). See also f.i. Vaughan (Geological mapping in the Western part of
the United States, Central Ametica and the West Indies. Proc. First Pan
Pacific Scientific Conference Honolulu 1921 Bd. Ill p. 695—705).

The oldest geological quotation of the Southern Santa Clara Province
we find in the book of 1. A. Wright 1916 (61) on the early history of Cuba.
On page 58 we read that in about 1513 in the surroundings of Xagua,
especially in the Rio Atimao gold was found. This was the reason why
Trinidad was founded.

In 1838 Berthier (6) published some notes on different minerals of
Cuba. From Villa Clara (this is Santa Clara) North of Tnnidad he mentions
an quot;arkosequot; with Cu carbonate and CuoO with a Copper content of 10.42 %;
moreover iron ore with mica, pyritc, copper-pyntc and quot;sous sulfate de
cuivrequot;, pure copper, gold-silver ore, etc.

In 1857 D. T. Ansted (3) gave a publication on the San Fernando
Copper Lodes, near Cienfuegos. The San Fernando Lode which has been
subject of some more papers (sec below) lies North of La Moza, near the
boundary of the Dioritic Intrusion and the Tuff Formation. Ansted mentions
the occurrence of granite, syenite, and also of porphyritic rocks in Central
Cuba. The San Fernando Lode is found North of these rocks in an area
\yith porphyrites and conglomerates, while N. and W. it is surrounded by
limestones, striking E—W, dipping N. The ore body comprises carbonates
and oxydes. We did not visit the locality, but from the description of Ansted
it is clear that it is to be found in the Tuff Formation near the Dioritic
Intrusion.

In 1864 Manuel Fernandez de Castro (9) states the finding of croco-
diles and Megalonjgt;i near Ciego Montero.

In 1876 the same author (10) published a quot;Catalogo de los Fosiles
de la Isla de Cubaquot;.

In 1884 the first geological map of Cuba by de Castro and Salterain
y Legara appeared. On this map the Sierra de San Juan and the Sierra de
Trinidad are indicated as quot;(Palaeozoico) Silurico Carboniferoquot;, while the
Sierra de Sancti Spiritus as quot;Terciariosquot;. North of the Schist mountains they
indicated quot;Hipogenicos igneos: Granito, Serpentino, Basaltoquot;. AllMesozoic
rocks they indicated with one colour. It is useless to compare this map with
our map of Southern Santa Clara Province as the scales largely differ. De
Castro (11) mentions in the centre of Cuba schists of probably Palaeozoic
age, possibly, however, they may be older or younger; Tertiary in the Sierra
de San Juan, and a granitic syenitic meseta near Cumanayagua. Moreover
unimportant mountains of diorite, andesite, serpentine and diabase quot;que
parecen haber trastornado las capas del periodo Cretaceoquot; (p. 150). Obvi-
ously de Castro was already of the opinion tKat the diorites and serpentines
are Cretaceous or Post-Cretaceous. The Tertiary hes flat although quot;pro-
fundamente denudadaquot;. To the W. of Cienfuegos on the banks of the Rio
Damuji, Cretaceous fossils are found {Hokctypus, Discoidea, Cassididides,
Codiopsis and others) together with Tertiary ones {Asterostoma, Aetobatis
poeyi, Encope ctae\ which occur in horizontal beds. Near Ciego Montero
Crocodilus pristinus, Testudo cubensis, Megalonyx rodens and Miomorphus cubensis
are found in Quaternary rocks with several young marine deposits.

In 1881 CoTTEAU (13) gave a description of 20 fossil Echinid species
from Cuba without finding places.

In 1892 Carlos de la Torre (50) mentions an Ammonite found in
Los Banos de Bija (cerca de Cruces). The exact locality is not known to me.

In 1914 the same author together with W. D. Matthew (53) states the
finding of four genera of Mammals in the Plistocene. A complete skeleton
of Megalocnus was fitted.

In 1915 de la Torre begins a quot;Revision de la Fauna cubanaquot; (51).

In 1916 the same author presents to the Sociedad Cubana de Historia
Natural quot;Fehpe Poeyquot; an account on the above mentioned fitted Megalocnus
skeleton (52).

In 1895 Adan de Yarza (1) describes granites and granuHtes from the
Rio Arimao near Cienfuegos.

In 1896 J. W. Spencer (46) published a paper on the Geographical
evolution of Cuba. He describes the Trinidad mountains, in which tilted
valleys and deep young canons. In the quot;Metamorphic Formationquot; he found
limestones and calcite-mica rocks', in the igneous Formation diorites,
quot;strata of serpentinequot; and some granites. He considers these rocks to be
older than the Cretaceous sediments on Cuba. From the east flank of the
Trinidad mountains and from the underground of the Trinidad valley he
describes limestones and sandstones. According to Spencer, Mathew has
described from the W. flank and from the neighbourhood of Cienfuegos
the same rocks with Cretaceous fossils as Exogyra, Ostrea, Inoceramus and
Hippurites, Caprinula and Caprotina. I am very sorry that it was impossible
to consult Mathews paper in Holland. In the neighbourhood of Trinidad

in the coast chain, and near Sancti Spiritus Spencer found Tertiary rocks
with rounded quartz material.

In 1899 Hill published a book on Cuba and Porto Rico (21) with a
small geological map of the island adapted from the map of de Castro
and Salterain. The geology is treated only in a footnote.

In 1901 a report on a geological survey of Cuba by C. W. Hayes, T. W.
Vaughan and A. C. Spencer appeared (20). In the same year Vaughan (56)
published a paper on the Copper Mines of the district. These papers are
important. The map of Castro—Salterain has been added to the paper
of Hayes c.s. The authors regard the schists together with the serpentines
and granites as basement rocks. The crystalline limestones and schists of
the Trinidad mountains are considered to be of Palaeozoic age. They found
Mesozoic limestones with Barrettia, Monopleura and Requienia etc., lying on
an arkose existing of fragments of serpentine and granite. As is evident from
our survey, the serpentine and diorite do not belong to the basement, but
are of Upper Cretaceous age, younger than the Schist Formation and the
Tuff Formation. The three authors doubt the existence of Eocene in Santa
Qara. They mention Upper Oligocene, although they did not find fossils
in it. They suppose that in Miocene time the whole island was emerged
above the sea. Diorite-porphyrites, diabases and gabbros are mentioned from
Southern Santa Clara. Hayes c.s. presume that Santa Clara consists of an
anticlinorium built of many regular folds or domelike elevations with the
axes E.—W. Moreover the several Copper Mines N.W. of Manicaragua are
treated by Vaughan who refers especially to the observations of Ansted,
Spilsbury and La Sagra, as Vaughan himself could not enter the aban-
doned and partly inundated mines.

In 1913 Barnum Brown (7) describes exhumations of fossils near Ciego
Montero and Jatibonico.

In 1915 Juan P. Ros (34) described granites from Arimao near Cuma-
nayagua. Fle says on page 422 quot;He visto el granito, tambien perturbando
notablemente las formaciones sedimentarias, calizas del Rio San Juan de
Letran en Trinidad en su nacimicntoquot;. Moreover he saw gneiss in the
rivers near Cumanayagua, Manicaragua and Barajagua quot;proccdentcs de la
alteracion del granitoquot; (p. 425).

G. de Usera (55) 1917 gives some informations on the three Copper
Mines near Manicaragua: San Fernando, Santa Rosa and Santa Helena,
which, according to him lie in the diorite area.

A thesis of Domingo F. Ramos in 1915 (33) treatcs the history of the
mineralogical and geological studies on Cuba.

The paper of De Golyer (15) on the geology of the cuban petroleum
deposits is of no special value for our district.

In 1919 W. D. Mathew (26) gives an extensive description of verte-
brates from Cicgo Montero {Megalocnus, Crocodilus). In 1931 (27) the same
author describes genera and new species of ground sloths from the
Plistocene of Cuba.

Luis Garcia Lorenzano 1925 (24) describes the occurrence of an
asbestos variety, amiante, in the finca Ojo de Agua, 20 km. from Trinidad
in serpentine (locality unknown to me). He added a small sketch map of
the region.

Antonio Calvache resumed in 1926 (8) the mining history of Cuba.
He stated that in the sixteenth century gold was found in the sands of the
Rio Arimao, Rio Agabama and Rio Caonao. South of Cumanayagua a large
pyritc deposit was found. Probably the Mina Carlotta is meant here.

In 1928 Roque Allende (2) treated the Mina Carlotta (M. 254). The
ore body is indicated as a conformable intercalation in gneisses and lime-
stones, while the occurrence of acid and basic rocks is mentioned.

In the catalogue of the quot;Instituto Nacional de Investigaciones Cien-
tificos y Museo de Historia Naturalquot; in Habana by Sanchez y Roig,
gold from Sancti Spiritus, pyrolusite from Santa Clara, grano-diorite
from Sancti Spiritus, pegmatite, tremolite-limestone and mica-schist from
Santa Clara are mentioned (43).

Alexander Wetmore 1928 (60) describes bad material of bones of
birds from Ciego Montero.

In 1932 J. Whitney Lewis (23) published a paper on the geology of
Cuba. In this paper a geologic map of the island was added. In consequence
of the small scale of this map it is impossible to compare it in detail with
our map of Southern Santa Clara Province. Nevertheless there are enormous
differences with our observations as any reader of both publications can
see. Lewis has treated the geology of Southern Santa Clara only in a general
way. Therefore it is of no use to compare in detail his results with ours.

R. H. Palmer (31) described several new Rudists from Cuba amongst
which Orhjgnia guitarti Palmer, Orhignja sanche^i Douvillé, Praebarrettia
sparcilirata var. cubensis Palmer n. var., Praebarrettia porosa Palmer and
Chiapasella bermude'^i Palmer from Sancti Spiritus. The determinations of
the first four species very probably are wrong (see 47).

In 1934 the same author published a paper on the geology of the sur-
roundings of Habana city. From this study we took the names for the Upper
Cretaceous Habana Formation and the Oligo-Miocene Guines limestones,
as these formations seem to outcrop over large distances on the island,
carrying the same Upper Cretaceous, respectively Oligo-Miocenc faunas.

Dorothy K. Palmer (28) and T. W. Vaughan (57) in 1934 stated the
age of Gallowayina browni, which is a synonym of Orbitoides bromiiy to be
Upper Cretaceous. Dorothy K. Palmer moreover worked on interesting
Larger Foraminifera (29).

In 1935 H. M. E. Schürmann (45) published a paper on the quot;Massen-
gesteine aus Cubaquot;. Seven analyses from Cuban igneous rocks arc given,
amongst which a granodiorite from Cumanayagua. On the whole our obser-
vations agree well with the general statement on the geology of the island
given by the author. According to Schürmann the serpentines are synoro-
genetic and the granodiorites postorogenetic. Since we found protoclastic

phenomena in the quartz-diorites, they must have been synorogenetic too.
The strong cataclasis, which sometimes produced mylonitization, prove
that the diorites have been affected by strong orogenetic stresses. As we
did not find in the Upper Cretaceous Habana Formation so strongly altered
cataclastic rocks, the orogenesis must have occurred during and after the
dioritic intrusion.

In 1935 a large compiling study from Schuchert (44) concerning the
Antillean Caribbean Region appeared. In Chapter 34 Cuba is treated. He
gives a compilation of the geologic knowledge of the island and tries to
place it in a scheme of his general conception of the Antillean Caribbean
Region. New geological data are not given.

The papers of L. Rutten (36, 37, 38) and M. Rutten (39, 40, 41) are
based on the observations of the same survey as the present paper. Where
necessary I quoted them in the text.

BIBLIOGRAPHY.

(1.) Adan de Yarza, Ramon, 1895 : Rocas hipogenlcas de la isla de Cuba.

Bol. Com. Mapa Geol. Espana, XX (1893) 1895, pp. 71—88.
Lam. I—IV.

(2.) Allende, Roque, 1928 : Yacimientos piritosos de la Sierra de Trinidad.

Mina quot;Carlottaquot;. Cuba, Direc. Montes y Minas Bol. de Minas,
12, pp. 50—57.

(3.) Ansted, d. t., 1857 : On the San Fernande Copper Lodes near Cien-
fuegos. Quart. Jour. Geol. Soc. London, J 3, pp. 240—243.
(4.) Anthony, H. E., 1925—1926: Mammals of Porto Rico, living and
extinct. Sc. Surv. Porto Rico and the Virgin Islands. New
York. Ac. Sc. IX, 1, 2; pp. 1—238, 54 plates and 3 maps.
(5.) Bennett, H. H. and Allison, R. V., 1928: The soils of Cuba.

Washington. Tropical Plant Research Foundation, 1928,
XXIV and 410 pp. 2 maps.
(6.) Berthier, 1838: Notes sur différents minerais de File de Cuba.

Ann. des Mines. (3) XIII, pp. 691—697.
(7.) Brown, Barnum, 1913: Some Cuban fossils. Am. Mus. Journal,

XIII, pp. 221—228.
(8.) Calvache, Antonio, 1925 : Resumen de Historia de la minen'a de Cuba.

Bol. de Minas Habana, 8, pp. 22—35.
(9.) Castro, Manuel Fernando de, 1864: De la existencia de grandes
mamiferos fossiles en la Isla de Cuba. An. Ac. Cub. Habana,
pp. 17—21, 54—60, 96—107.

(10.) -, 1876: Catdlogo de los fossiles de la Isla de Cuba. An.

Acad. Hab., 13, pp. 319—330.

(11.) -^ 1884: Pruebas paleontologicas de que la Isla de Cuba ha

estado unido al continente Americano y breve idea de su
constitución geologica. An. Ac. Habana, 21, pp. 146—165.
(12.) Corral, José J., 1929: Los primeros pasos de la mineria cubana.

Soc. Geogr. de Cuba, Rev. II, pp. 131—138.
(13.) CoTTEAU, 1881 : Description des Echinides fossiles de 1'ile de Cuba.

Ann. Soc. Géol. Belgique, IX. Mém. pp. 3—49, Pl. I—IV.
(14.) Daly, R. A., 1933: Igneous rocks and the depth of the earth.
(15.) De Golyer, E. L., 1918: The geology of Cuban petroleum deposits.

Amer. Assoc. Petrol. Geol., Bull. vol. 2, pp. 133—167.
(16.) Douvillé, H., 1926: Quelques fossiles du Crétacé supérieur de Cuba.

Bull, de la Soc. géol. de France, 4e sér., t. XXVI, pp. 127—138.

(17.) -, 1927: Nouveaux rudistes du Crétacé de Cuba. Bull, de la

Soc. géol. de France, 4e sér., t. XXVII, p. 49—56.

(18.) Ellis, B. F., 1932: Gallowayina hrowni, a new genus and species of
orbitoid from Cuba, with notes on the American occurrence
of Omphalocjclus macropora. Amer. Mus. Novitates, no. 568
8 pp.

(19.) Gilluly, j., 1935: Keratophyres of eastern Oregon and the spilite
problem. Amer. Journ. of Sc. fifth series. Vol. XXIX, No. 171
March.nbsp;'

(20.) Hayes, C. W., Vaughan, t. W., and Spencer, A. C., 1901 : Report
on a geological reconnaissance of Cuba, made under the direc-
tion of General Leonard Wood. In Civil Report of Brig.-Gen.
Leonard Wood, mihtary governor of Cuba, for the period
from January I to December 31, vol. 1,123 pp.

(21.) Hill, R., 1899: Cuba and Porto Rico with the other islands of the
West Indies. New York (Century), 447 pp.

(22.) Holme^ A., 1920: The nomenclature of Petrology. London (Murby

(23.) Lewis, J. W., 1932: Geology of Cuba. Amer. Assoc. Petrol. Geol
Bull. vol. 16, pp. 533—555.

(24.) Lorenzana, L. G., 1925: Informe geologico de unos terrenos en los
que se ban encontrado muestros de amianto. Bol. de Minas
Habana, 8, pp. 61—63.

(25.) Matthew, W. D., 1913: Cuban fossil mammals, preliminary notes.
Bull. Geol. Soc. Amer.

(26.)-, 1919: Recent discoveries of fossil Vertebrates in the West

Indies and their bearing on the origin of the Antillean fauna
Proc. Amer. Philos. Soc. LVIII, pp. 161—181.

(27.) -,1931 : Genera and New Species of ground sloths from the

Pleistocene of Cuba. Am. Mus. Novitates, no. 511 5 pp

(28.) Palmer, D. K., 1934: The Upper Cretaceous age of the orbitoidal
genus Galloway'ma Ehis. Jour. Pal., vol. 8, pp. 68—70.

(29.) -, 1934 : Some large fossil Foraminijera from Cuba. Soc. Cubana

Hist. Nat. quot;Felipe Poeyquot;, Mem. vol. VIII, no. 4, pp. 235—264

(30.) Palmer, R. H., 1928: The Rudistids of Southern Mexico. California
Acad, of Sciences, Occ. Paper XIV.

(31.) -, 1933: Nucvos rudistas de Cuba. Rev. Agric., Havana vol

14, pp. 95—125.nbsp;^

(32.) -, 1934: The geology of Habana, Cuba, and vicinity. Jour.

Geol., vol. 42, pp. 123—145.

(33.) Ramos, D. F., 1915: Bosquejo historico accrca de los estudios minera-
logicos y geologicos relativos a la Isla de Cuba. Causa del
evidente atraso de los mismos. Soc. Cubana Hist. Nat. quot;Felipe
Poeyquot;. Mem. vol. I, pp. 37-^6, 56—67.

(34.) Res, J. P., 1915: Rocas de la Provincia de Santa Clara. Rev. de la Soc.
de Ingenicros. Habana. VII, pp. 420—426.

(35.) Rosenbusch, H., 1923: Elemente der Gesteinslehre. Stuttgart

(36.) Rutten, L., 1934: Geology of Isla de Pinos, Cuba. Kon. Akad. Wet.
Amsterdam, Proc. Vol. XXXVII, No. 7, pp. 401—406.

(37.) -, 1933: Grondkarteeringen in Nederlandsch Oost-Indië en

in Cuba. De Indische „Mercuurquot;, 27 Sept. en 4 Oct.

(38.) -, 1933: Algunos resultados de las investigaciones geologicas

de la comisión cientifica holandesa en Cuba. Rev. Soc. Geogr.
Cuba, Afio VI, Num. 3. pp. 47—52.
(39.) Rutten, M. G., 1935: Larger Foraminifera of Northern Santa Clara
Province, Cuba, Jour. Pal., Vol. 9, No. 6. p. 527—545.

(40.) -, 1936: Rudistids from Northern Santa Clara Province.

Jour. Pal. Vol. 10. p. 134—142.

(41.) -, 1936: Geology of the Northern part of the Province Santa

Clara, Cuba. Geogr. en Geol. Med., Utrecht, Physiogr.-Geol.
Reeks, No. 11.

(42.) sdnchez Roig, M., 1926: La fauna cretacica de la region central de
Cuba. Soc. Cubana Hist. Nat. quot;Felipe Poeyquot;, Mem., vol. 7,
pp. 83—102.

(43.) -, 1928: Institute nacional de investigaciones cientificas y

Museo de Historia Natural. Museo Catalogo.
(44.) schuchert, Ch., 1935: Historical geology of the Antillean-Caribbean

Region. New York.
(45.) Schürmann, H. M. E., 1935: Massengesteine aus Cuba. N. Jahrb.

Min. etc. Beil.-Bd. 70, Abt. A. pp. 335—355.
(46.) Spencer, J. W., 1896: Geographical evolution of Cuba. Bull. Geol.

Soc. Am. VII, pp. 67—94.
(47.) Thiadens, A. A., 1936: Rudistids from Southern Santa Clara, Cuba.

Kon. Akad. Wet. Amsterdam, Proc. Vol. XXXIX, No. 8,
pp. 1010—1019.

(48.) -, 1936: On some Caprinids and a Monopleurid from South-
ern Santa Clara, Cuba. ibid. Proc. Vol. XXXIX, No. 9, pp.
1132—1141.

(49.) -, 1937: Cretaceous and Tertiary Foraminifera from Southern

Santa Clara Province, Cuba. In press in Jour. Pal.
(50.) Torre, C. de la, 1892: Observaciones geologicas y palaeontologicas
en la sección central de la Isla. Acad. Cien. Habana, An., Vol.
29, pp. 121—124.

(51.) -, 1915: Revision del Catdlogo de la fauna Cubana. Soc. Cubana

Hist. Nat. quot;Felipe Poeyquot;. Mem. vol. 1. pp. 31—36.

(52.) -, 1916: Presentacion del esqueleto restaurado del Myomorphus

o Megalocnus rodens. Ibid. Mem. vol. II pp. 94—103.

(53.)-, and Matthew, W. D., 1914: Megalocnus and other Cuban

ground sloths. Bull. Geol. Soc. Am., 26, p. 152.
(54.) Trauth, Fr., 1936: Ueber Aptychenfunde auf Cuba. Kon. Akad. Wet.
Amsterdam. Proc. Vol. XXXIX, no. 1, pp. 66—76.

(55.) Usera, G. de, 1917: Informe sobre las minas de Cobre de Manicara-
gua. Bol. de Minas, Habana, 2, pp. 91—103.

(56.) Vaughan, T. W., 1901 : The Copper Mines of Santa Clara Province,
Cuba. The Eng. and Min. Jour. 72, II, pp. 814—816.

(57.) -, 1934: A note on Orbitoides browni (Ellis). Tour. Pal Vol 8

No. 1, pp. 70—72.nbsp;• • '

(58.) Vermunt, L. W. J., 1937: The Geology of Pinar del Rio Province,
Cuba. Thesis, Utrecht, In press.

(59.) Westermann, J. H., 1932: The geology of Aruba. Thesis, Utrecht.

(60.) Wetmore, Al., 1928: Bones of birds from the Ciego Montero deposit
of Cuba. Amer. Mus. Novitads. no. 301, 5 pp

(61.) Wright, L A., 1916: The early history of Cuba. 1492—1586 New
York 390 pp.

EXPLANATION OF THE PLATE.

Figures 1—11 are micro-photographs of thin sections; figure 12 is taken of the rock-sample.
Figures 1, 4, 7, 8, 9, 10 and 11 are taken with niçois crossed, figures 2,3,5 and 6 with ordinary polarized
light.

fig. 1. Serpentine schist of the Schist Formation with quot;Gitterstrukturquot;. Serpentine flakes arranged in
the direction of amphibole cleavages. 12^ km. N. from El Ingles, A 297 (D. 17019). x 30.

fig. 2. Uralite-porphyrite, with rest of augite phenocryst and many broom-like uralite bundles ^in the
groundmass. 3 km. N. from Manicaragiia, L. 338 (D. 16541). X 35.

fig. 3. Garnet-rock, showing the large broken garnet crystals, with zoning at the periphery. The space
between the garnet is filled in with quartz. 2J km. E. from Sancti Spiritus, M. 583 (D. 16759).
x 13^

fig. 4. Pyroxene-hooibergite, showing large amphibole crystals (below) and intergrown pyroxene and
amphibole crystals (upper half). 5 km S. from La Moza, L. 302 (D. 16491). x 9J.

fig. 5. Metahooibergite, with a large primary hornblende crystal with a dark rim, and a secondary
quot;groundmassquot; consisting of amphibole and plagioclase. 4J km. S. from Manicaragua, M. 217
(D. 16696). x 32.

fig. 6. Quartz-amphibole-biotite-diorite ; normal-coarse-grained at the right side, and finer-grained
and darker at the left side. Rio Arimao, 1 km. N. from Manicaragua, M.322 (D. 16748). x 9J.

fig. 7. Gneissic diorite, with mortar structure caused by cataclasis. 4J km. S. from La Moza, L. 301
(D. 16490). x 11}.

fig, 8. Amphibole-gneiss, with a dark band consisting almost entirely of undulatory hornblende in the
upper half part and in the lower half in one with a lighter band showing mortar-structure. 6 km.
5. from La Moza, L. 304 (D. 16498). x 28}.

fig. 9. Grano-diorite-aplite with granophyric intergrowth. Carretera Central 2 km. N. from Sancti
Spiritus, L.438 (D. 16583). X 28^.

fig. 10. Cataclastic grano-diorite-aplite, with mortar structure. 10 km. SE. from Manicaragua, L. 291
(D. 16483). x 35.

fig. 11. Cataclastic grano-diorite-aplite, with mortar-structure and beginning of foliation. 6,5 km. S.
from Manicarfgua, M. 229 (D. 16700). X 35.

fig. 12. Light diorite dike in hooibergite, with inclusion of dark quartz-frcc pyroxcnc-hooibcrgitc. 5 km.
S. from La Moza, L. 302. x 2.

STELLINGEN

I.

De groote diorietr en serpentynintrusies in Centraal Santa
Clara, Cuba, behooren niet tot de „basement-rocksquot; van
het eiland.

II.

Palaeozoische gesteenten zijn niet op Cuba aangetoond.

III.

De vraag, of de albiet in spilieten primair of secundair
is, is niet definitief opgelost. Dc argumenten voor secundaire
genese wegen zwaarder dan die voor primaire genese.

IV.

Het genus Praebarrettia moet vervallen.

V.

Ten onrechte noemt Cvijió de morphologische niveaux
in de Sumadije abrasie-terrassen. Deze niveaux zijn veeleer
te verklaren door fluviatiele werking.

J. Cvijic: Jezersk.1 phistik.i Sumadije. Glasn. Srpskc Kral.

Ak. Bd. 79, 1909.

VI.

Het ware toe te juichen, indien de studenten in de geologie
reeds djdens hun studie door middel van practisch werk
kennis konden maken met het groote belang van luchtphoto-
graphiecn voor de géomorphologie en geologie.

ym'Mismr-. ;

■ ■nbsp;■ ■ -.C.nbsp;.nbsp;■nbsp;■.....■ ■ .

M'

■'à,..

.....

^'yr.^y- hf: .

ft*- : .

:

fc ; s:/ .-'iy- ' ; ; ■

VJI.

Bederkes verklaring van de metamorphose in het Altvater-
gebirge is door haar hypothetische en gekunstelde aard niet
te verkiezen boven de vroegere opvattingen.

Erich Bederke : die Regionalmetamorphose im Altvater--
birge. Geol. Rundschau Bd. XXVI, 1935 Heft ^jl ^

Vin.

Tusschennbsp;en Amph'sorus bestaan geen generieke

verschillen.nbsp;^

IX.

Het bestaan van een Praecambrische geosynclinale langs
de Noordkust van Groenland is door Koch niet voldoend
aangetoond.

Geologie der Erde: Lauoe Koch, Geologie von Grönland

X.

De opvatting, dat men om economische overwegingen de
verwerking der grondstoffen zoo dicht mogelijk bij hun
productiecentra moet laten plaats vinden, geldt niet voor
de petroleumindustrie.

PROVINCIAL LIMESTONESnbsp;SCHIST fORMATION

IS km.

^mm

,, ■ ■nbsp;.'-■•Ii., . -

Mi

mMm