498 Guppy — West Indian Geology. 



of Upper Miocene date. For although the Scotland formation is 

 different in its general appearance and composition from the Upper 

 Miocene of San Domingo, Jamaica, Trinidad, and Cumana, yet it 

 bears in part a similarity to that of Trinidad, in its included and 

 characteristically abundant minerals ; namely, petroleum, coal, and 

 selenite. 



It may perhaps be inferred from the discovery of Nucula Schom- 

 hurgki in the Lower Miocene of Trinidad that after the deposition 

 of that formation a depression took place, which led to the existence 

 of a deep ocean over part of the West-Indian area. This is in- 

 dicated by the Polycystina beds of Barbados, whose fossils resemble 

 those dredged from great depths in the sea."^ 



As the Nucula SchomburgM is an interesting form, I have made a 

 drawing of the best-preserved example, and three other fossils from 

 the same bed are also figured herewith, together with some other 

 species of mollusca from Miocene deposits in the West-Indies ; and 

 which are not only interesting from their zoological affinities, but 

 may aid in the identification of rocks of the Tertiary period in the 

 Caribean area. 



3. In the lists of fossils I gave in my paper on the Relations of 

 the West-Indian Tertiaries, the name Ancillaria glandiformis should 

 have been included in the San Domingan and Jamaican lists. I am 

 satisfied from the figures of this variable shell, given by Homes, in 

 his Fossil Mollusca of the Vienna Basin, that the Ancillarics in the 

 collection of the Geological Society belong to this species, and also 

 the small and young examples from Jamaica, in the British Museum. 

 Another link is thus added to those which already connect the 

 European and Caribean Miocene. The shell I described in the 

 same paper as Melanopsis cepula (not capula, which is a misprint), 

 seems to be deserving of generic rank, and I propose to distinguish 

 it by the name Crepitacella. The characters are appended hereto. 

 The shell described by me under the name of Malea camura occurs 

 in San Domingo as well as in Jamaica.* 



4. As a further result of my researches, I may here state that 

 I find myself gradually tending towards the belief that the Tamana 

 series and the San Fernando beds in Trinidad must be separated 

 from the other deposits in the West-Indies termed Miocene ; and 

 that it would be more correct for the present to limit the term Lower 

 Miocene to the former, and to class the Anguilla and Antigua Beds 

 as the lower members of the Upper Miocene. I propose, therefore, 

 the following classification of the Caribean Upper and Middle 

 Tertiaries : — 



1. Pliocene. 



a. Barbados, Guadeloupe, etc. 



b, Trinidad (Matura Beds). 



1 See Maury, Phys. Geogr. of the Sea (1858), pp. 254, 263. 



2 The shell from San Domingo, in the British Museum, labelled Venus circinaria, 

 is not that species, but more probably Venus rigidafV. rugosaj. 



