The Trinidad Geological Conference was held on the island of Trinidad, B.W.I., April 18-27, 1939, and was attended by approximately 40 geologists from Trinidad, British Guiana, the West Indies,

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Click to view image in GIF format. Fig. 1. [Grey Scale] Group of geologists attending Trinidad Geological Conference, April, 1939.

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Europe, and the United States. This conference was sponsored by the Petroleum Association of Trinidad with the cooperation of the oil companies and the Government of Trinidad. It is the third of a series of geological conventions held in this region in the last few years--the first being the Venezuelan Geological Congress in Caracas in 1937, and the second being the Venezuelan Geological Congress in San Cristobal last year.

The objects of the present conference were stated as follows.

1. To express to the Venezuelan Government the gratitude of the geologists of Trinidad for the generous invitations to the First and Second Venezuelan Geological Congresses; also to the oil companies operating in Venezuela for their liberal scientific contributions to these congresses.

2. To introduce the geologists of Venezuela to stratigraphical details of the geology of Trinidad on the assumption that interchange of knowledge will be of practical value to all.

3. To foster the good accord engendered by the Venezuelan Government in establishing closer cooperation and creating a spirit of mutual understanding between the two oil-producing countries on either side of the Gulf of Paria.

The major feature of the Conference was the series of excellently organized field excursions under the able leadership of Hans G. Kugler, chief petroleum geologist of the Central Mining and Investment Corporation, Ltd. These excursions occupied 6 days during which the attending geologists were taken over the whole island, visiting the classic fossil localities, points of critical stratigraphic importance, type localities and sections, and areas of special structural interest. These trips were made particularly enjoyable by the beautiful and varied natural scenery of the island.

Excursion No. 1:
Trinidad Northern Range, particularly the extreme northeastern part of the island. Greenstone intrusion of Sans Souci with surrounding Upper and Middle Cretaceous sediments--phyllites of southeastern slope of Northern Range--metamorphosed limestones of Hollis Water Reservoir where Jurassic ammonites have recently been found.

Excursion No. 2:
East-central part of island. Fossil localities in Upper Miocene-Pliocene Talparo formation and Miocene Brasso and Nariva formations--remnants of Middle Cretaceous limestones--equivalents of the Pointe-a-Pierre grits--coral and algal reef limestones of Biche and Tabaquite.

Excursion No. 3:
West-central part of island; vicinity of Pointe-a-Pierre and San Fernando. Classic type localities of Bon Accord conglomerate, San Fernando argiline, Pointe-a-Pierre grits, Mount Moriah

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formation, Vista Bella and Point Bontour limestones, Cipero group, Springvale beds, et cetera.

Excursion No. 4:
South-central part of island. Mud volcano of Devil's Woodyard--fossil mudflows--Paleocene Marac Quarry limestone--remarkable study in contemporaneous deformation of Palo Seco beds along southern shore of island--classic Morne Diablo Quarry.

Excursion No. 5:
Southwestern part of island. Type locality of upper Forest Clay--Morne l'Enfer sands--La Brea formation--porcellanites due to burning of lignite beds--mud flows--famous pitch lake of Brighton.

Excursion No. 6:
Patos Island near Venezuelan shore. Phyllites and limestone of uncertain age.

Excursion No. 6 (alternative):
Forest and Apex oil fields.

The island of Trinidad has been subjected to intensive study by oil-company geologists for the last 30 years and proportionally much more stratigraphic and structural detail is available here than in most of the neighboring areas of the West Indies and South America. The Trinidad Conference furnished an excellent opportunity for the geologists of neighboring countries to share in the benefits of the geological progress on this island. However, because of the peculiarly complicated structure and rapid facies changes in this area, many points of structure and stratigraphy still remain to be solved and the visiting geologists were introduced to a number of intriguing and as yet unsettled problems.

Two days of the conference were devoted to the reading and discussion of papers. What little time remained between field trips and meetings was filled by a number of social affairs in which the guests and their families were very pleasantly entertained.

At the closing session on April 27 an invitation to the Third Venezuelan Geological Congress in 1940 was extended by Guillermo Zuloaga of the Venezuelan Servicio Tecnico de Geologia y Mineria.

There were fifteen members of the A.A.P.G. present at the conference and in their behalf gratitude and appreciation are here expressed to R. S. Mackilligin (inspector of mines and petroleum technologist); to H. G. Kugler who so ably conducted the field excursions and through whose efforts the Conference was largely brought into being; to A. G. Hutchison who assisted in the organizing of the excursions; to E. C. Scott, secretary; to N. Betancourt, C. C. Wilson, and A. E. Gunther of the organization committee; and to the many others who contributed to the success of the Conference.

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ABSTRACTS

Papers presented at the 1939 Trinidad Geological Conference will be published in full during the year in both English and Spanish in the Venezuelan Boletin de Geologia y Mineria which may be obtained from the Servicio Tecnico de Mineria y Geologia, Ministerio de Fomento, Caracas. Brief abstracts of these papers are given here.

KUGLER, H. (Central Mining and Investment Corporation, Ltd.): Our Present Knowledge of the Geologic History of Trinidad.

In a brief but comprehensive review of the stratigraphy and geologic history of Trinidad the author touches particularly on recent discoveries and brings out the latest thought on the general geology of the island. He discusses the correlation of Trinidad formations with those of the mainland and calls attention to a number of unsolved problems in the stratigraphic succession of the island.

SCHMID, K. (Trinidad Leaseholds, Ltd.): The Classification of Rock Units and the Definition of Formations in Trinidad.

The principles of stratigraphic nomenclature are discussed, and group and formation names are suggested for Upper Tertiary stratigraphic units in the Fyzabad fields of southern Trinidad and in the northern basin and Central Range. These names are proposed tentatively for consideration and formal definition of the units is not attempted. Detailed stratigraphic charts are presented for both areas.

HUTCHISON, A. G., and TERPSTRA, G. R. J. (United British Oil Fields of Trinidad, Ltd.): A Note upon the Biche Quarry Limestone, Trinidad.

This limestone is one of a series of local algal and foraminiferal reef limestones in the Lower Miocene of the Central Range. The lithology, structure, and micropaleontology are discussed in detail and evidence for Lower Miocene age is given.

RENZ, H. H., and SUTTER, H. H. (Trinidad Leaseholds, Ltd.): The Pozon and El Mene de Acosta Type Sections of the Agua Salada Formation.

A type section is designated for the Agua Salada formation (Upper Oligocene to Middle Miocene age) of eastern Falcon, Venezuela, and the formation is defined and described. Particular emphasis is given to the foraminiferal fauna of this formation. The formation of the type section includes seven named foraminiferal zones with 144 species. The foraminiferal fauna of the Agua Salada is closely related to the fauna of the Carapita and Santa Ines formations of eastern Venezuela and to the Brasso and possibly the Springvale formations of Trinidad. The paper is accompanied by excellent maps, sections, and species distribution charts.

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RUTSCH, R. (Natural History Museum, Basel, Switzerland): Evolution of Tropical American Tertiary Faunas and Theory of Continental Drift.

In this paper the author calls attention to the close relation between Paleocene and Eocene benthonic mollusk of northern Africa and tropical America. He believes this relationship is so close that the existence of an Atlantic Ocean in its present form is almost precluded as far as the oldest Tertiary is concerned. During the Oligocene and Miocene the differentiation is more clearly defined, the faunas more closely approaching their present individuality. The author concludes that while the close connections between the oldest tropical American and south European-North African Tertiary faunas can be explained by several theories, the continental-drift theory of Alfred Wegener is the most probable.

HUTCHISON, A. G. (United British Oil Fields of Trinidad, Ltd.): A Note upon the Jurassic in Trinidad, B.W.I.

Upper Jurassic ammonites (identified by L. F. Spath of the British Museum as Perisphinctes transitorius Zittel) were recently found in limestones interbedded with phyllites at the Hollis Reservoir on the south flank of the Northern Range of Trinidad. This is a discovery of major importance as definitely proving the Jurassic age of at least a part of the metamorphic rocks making up the Northern Range.

WILSON, C. C. (Trinidad Petroleum Development Co., Ltd.): The Los Bajos Fault of South Trinidad.

The Los Bajos fault of late Miocene or Pliocene age cuts across the southwestern peninsula of Trinidad with a strike of about North 70° West from Pt. Ligoure on the western coast to the vicinity of Negra Point on the southern coast. In its western part there is an apparent downthrow of 7,000 feet to the south while in its eastern part there is an apparent downthrow of 4,000 feet to the north. The author believes this fault to be essentially a strike slip fault with the northern side moving eastward relative to the southern side and the apparent throw at the fault line resulting from the discordant juxtaposition along the fault of folded structures developed previous to the fault movement. In the western part of its course the differential horizontal movement amounts to as much as 8 miles. The fault has played a major role in influencing the migration and accumulation of oil and its course intersects several major oil fields. The origin of this fault is explained by the author as due either to (1) "gravity collapse" of incompetent sedimentary filling of the Orinoco basin, or (2) crustal adjustment related to drift movement of the American continents.

GUNTHER, A. E., and TERPSTRA, G. R. J. (United British Oil

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Fields of Trinidad, Ltd.): A Note upon Some Recent Additions to the Upper Cretaceous of Trinidad, B.W.I.

Upper Cretaceous deposits of cherts and marls have recently been discovered in the eastern part of the Central Range. Samples from these beds have yielded a foraminiferal fauna believed to be older than the Lizard Springs fauna described by Cushman and Jarvis and believed to be equivalent in age to the Mendez of Mexico.

SENN, A. (British Union Oil Company): The Paleogene of Barbados and Its Bearing on the History and Structure of the Antillean-Caribbean Region.

The author discusses in detail the stratigraphic sequence of Barbados.

Scotland formation (Lower and Middle Eocene)
Joes River formation (mudflow of Upper Eocene age)
Oceanic formation (Upper Eocene and Lower Oligocene)
Bissex Hill marl (Upper Oligocene)
Coral rock (Pliocene-Pleistocene)

Evidence is given for the ages assigned to these formations and correlation with other parts of the Caribbean region is discussed. The importance of Upper Eocene orogeny in the Caribbean region is stressed. A resume is given of the geological history of the Antillean-Caribbean region in which it is concluded that during the Upper Cretaceous and Eocene a land or shallow water connection existed between the Caribbean and European Mediterranean regions but that this connection was broken during the Upper Eocene orogeny. A comprehensive correlation chart for the Caribbean region is presented.

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