194 R. J. L. Guppy — Rock-horhirjs, Trinidad. 



the Proceedings of the Victoria Institute, Trinidad, 1902, and the 

 Journal of the Geological Society of London, 1892. 



With one exception the rock appears to be of the same quality 

 and consistence throughout. At 500 feet occurs a harder bed 

 composed of similar material to the other beds, but indurated and 

 not liable, as the other beds are, to disintegration by water. This 

 harder bed contains only traces of calcareous matter, and much fewer 

 organic remains than the others. 



I have no particulars of the material found at intei'uiediate depths, 

 but presuming that it is uniform or nearly uniform throughout it 

 would appear that we have here a thickness of more than 500 feet 

 in depth of very fine sedimentary material, probably deposited in 

 a sea somewhere about 20 to 50 fathoms deep. It might even have 

 been more, but to ascertain this other circumstances not at present 

 known would have to be taken into account. The deposition of so 

 extensive a stratum of such material implies a long period of time 

 during which the conditions of the area on which deposition was 

 taking place remained generally the same. 



The molluscan and other organic remains exist entire within the 

 matrix, but being for the most part in the state of powder they 

 cannot be extracted. The Foraminifera and a very few MoUusca and 

 Ostracoda alone are of a sufficiently compact consistency to stand 

 extraction by washing, which is the only mode of operation practicable, 

 as any attempt by more forcible means results in the complete 

 disintegration of the fossils. 



Doubtless also here, as in the Naparima and Pointapier beds, 

 many Foraminifera appear as fragments only, such as Rhabdammina, 

 Haliphijsema, Dendroplujn, etc. But leaving apart such oi-ganisms 

 as these, there will be, if occasion serves in the future, an enormous 

 extension of this list of fossils. 



MOLLUSCA. 



Balantiiim. Plenrotoma. 



Bulla. Nuada. 



Dolmm. „ 



Fusus. Pecien. 



The only specimens extracted were a Pecten and a Niicida (single 

 valves). One valve of a Pecien is ornamented with radiating 

 elongate-elliptical blotches of purplish-brown colour, showing how 

 persistent the original colouring must have been to have been 

 preserved in such decolorizing material as that of which these beds 

 are composed. 



POLYZOA. 



The only generically identifiable one is Cupidaria, but others 

 seem to be Memhranipora, etc. 



OSTRACODA. 



Bairdia woodwardiann, Brady ; CytliereUa polita, Brady. There 

 is also a prawn-like crustacean over an inch long. 



