THE TERTIAKT MICKOZOIC EOEMATIONS OF TRINIDAD. 519 



39. The Teetiaey Microzoic Formations of Trinidad, West Indies. 

 By E. J. Lechmere Guppy, Esq. (Communicated by Dr. H. 

 Woodward, F.E.S., F.G.S. Eead June 8tli, 1892.) 



Contents. 



Page 



§1. Introduction 519 



I 2. The Stratigraphy of the Naparima Beds 520 



I 3. Physical and other Characters of some of the Naparima 



Microzoic Eocks 525 



§ 4. The Pointapier Section 530 



§ 5. The Foraminiferal Fauna -. 532 



I 6. General Conclusions 535 



Appendix 538 



§ 1. Introduction. 



The island of Trinidad is separated from Venezuela and the great 

 delta of the Orinoco by the Gulf of Paria, which stretches for 100 

 miles from east to west, and opens northward into the Caribean 

 Sea by the Bocas del Drago (Dragon's Mouths), and southward into 

 the Atlantic Ocean by the Serpent's Mouth. 



The Microzoic Deposits of Trinidad form a zone 10 miles broad 

 from N. to S., and about 35 miles long from E. to W. Whether 

 they occur or not on the mainland of South America is not known, 

 but from considerations which will appear in the course of this 

 paper I think it probable that they do not. 



The strike of the beds varies between N.E. & S.W. and E. & W. 

 It will be noticed that, on the whole, it corresponds with the trend 

 of the coast of the Gulf of Paria south-westward from Sipero 

 Creek, near San Fernando. On the east the microzoic formations 

 rise out of the swamps that fringe that shore of the island, while 

 westward they sink below sea-level in the Oropuch Lagoon. They 

 are bounded to the north by strata presumed to be of Cretaceous 

 age, and to the south by Miocene and Pliocene rocks of mainly 

 arenaceous character. 



The sketch-map facing this page exhibits the relationship of the 

 Microzoic Deposits to the chief physical features of the region, and 

 indicates the shore-line of the supposed ancient continent. 



As regards the literature of the subject, the reader may consult 

 Messrs. G. P. Wall and J. G. Sawkins's ' Eeport on the Geology of 

 Trinidad,' published in 1860. The practical difficulties with which 

 those surveyors had to contend were such as to prevent their 

 Eeport from being more than a general outhne. 



The Naparima Marls, mentioned in that Eeport as exposed for 

 some distance in the cliffs north and south of San Fernando, were 

 treated of three years later by the present writer in a communica- 

 tion to the Scientific Association of Trinidad,^ and again in 1866.^ 



1 Eeprinted in the ' Geologist ' for 1864, p. 159. 



2 Quart. Journ. Geol. See. vol. xxii. (1866) p. 571. 



