MIOCENE GASTROPODS AXD SCAPHOPODS FROM 

 TRINIDAD, BRITISH WEST INDIES ' 



By Wendell C. Maxsfteld 

 Of the United States Geological Survey 



INTRODUCTION 



The object of this paper is to describe some inadequately known 

 Miocene gastropods and scaphopods from a few localities in Trini- 

 dad. British West Indies, and to determine, in so far as practicable, 

 their stratig-raphic position with respect to the standard section of 

 the Atlantic and Gulf Coastal Plain and the West Indies, 



PRINCIPAL PDBLICATIONS ON THE GEOLOGY AND PALEONTOLOGY OF TKINIDAD 



Wall, G. P., aud Sawkins, J. G., Report on the Geology of Trinidad : London, 

 1860. 



In the treatise ou the descriptive geology the rocks are separated into three 

 groups — Caribbean group, the Older Parian group, and the Newer Parian 

 group. The Newer Parian group is again separated into five divisions or 

 series, arranged in stratigraphic age sequence from the lowest up as follows : 

 Nariva series, Naparima marl, Tamana or calcareous series, Caroni or Car- 

 bonaceous series, and Moruga or arenaceous series. The age of the Caribbean 

 group is uncertain I)ut is regarded as antedating the Older Parian ; the Older 

 Parian is tentatively assigned to the Lower Cretaceous ; and the Newer 

 Parian is questionably assigned to the Miocene. The geologic map accompany- 

 ing the report is the only one now available. 



Although some of the results outlined are not conclusive, the report is an 

 admirable example of scientific work on pioneer geology in an area beset with 

 many difiiculties. 



Guppy, R. J., Lechmere and Dall, W. H., Descriptions of Tertiary fossils from 

 the Antillean region: U. S. Nat. Mus. I'roc, vol. 19, No. 1110, pp. 30.3-331, 

 4 pis., 1S96. In this publication fifteen new .species of moUusks are de- 

 scribed by Guppy from Trinidad. 



Guppy was intensely interested in the geology of Trinidad as well as other 

 areas, and his contributions to both paleontology and stratigraphy are a val- 



' Dr. Carlotta Joaquina Maury's paper "A further contribution to the Paleontology of 

 Trinidad" (Miocene horizons), published as Bulletin 42 of American Paleontology, volume 

 10, appeared while my paper was in corrected page-proof form and in Ihe hands of the 

 editor ; consequently the page proof was recalled and necessary revisions made. 



The principal revisions consisted in the substitution of nine names of Doctor Maury"s 

 species for the names of the same forms which I had described as new, but retained my 

 own descriptions. References to her descriptions were inserted in the synonymy. 



The " Outline of results " in my paper was not changed. In this connection, however. 

 Doctor Maury has placed in the lower Miocene the fauna at Brasso Creek, which I 

 infer is the locality represented by my station numbers 8.302 and 9212, and at Guaica- 

 Tamana Road, thirteenth mileiwst, which appears to be the locality represented by my 

 station 9219 ; the former she referred to the Manzanilla Miocene and the latter to the 

 stratigraphically lower Machapoorie Miocene. Doctor Maury"s interpretation of the 

 age of the faunas, based on her study of both the gastropods and the pelecypods, sug- 

 gests to me a stronger probability that the fauna at my station 9219, and perhaps some 

 of the possibly mixed faunas from the stream wash 1 mile south of Brasso, belong to the 

 lower Miocene, though I regard the fauna at station 9219 as a little higher stratigra- 

 phically than that at Machapoorie Quairy. 



No. 2559. — Proceedings U. S. National Museum. Vol. 66, Art. 22 



9116—25 1 I 



