TERTIAEY MICSOZOIC TOEMATIOISI'S OF TRINIDAD. 



527 



shells has been altered or removed. 

 The exact nature of the bodies 

 which have thus disappeared is not 

 clear; but it may be inferred that 

 they were foraminifera, radiolaria, 

 and other small organisms. I have 

 noticed one more definite fossil, appa- 

 rently the spine of an Ophiu7'a. 



It seems then that we have here 

 a deep-water deposit very similar 

 in its origin to the radiolarian 

 beds of Naparima aad elsewhere. 

 But what are its relations to the 

 Naparima Marls ? Though no exist- 

 ing sections show those relations, it 

 is probable that it is of more ancient 

 date. It is true that direct evidence 

 of superposition is wanting, but there 

 can be little doubt on this point. 

 Naparima Hill is higher than any 

 other ground within several miles, 

 rising as it does to 500 feet above 

 sea-level, while the general surface 

 of the country is under 200 feet.^ Is 

 this superior height due chiefly to the 

 elevation of the beds forming the hill 

 by subterranean forces, or entirely 

 to the degradation of the more de- 

 composable Naparim a marls? Viewed 

 from the Gulf the hill seems to rise 

 out of a crater-like depression. This 

 appearance is caused by the large 

 ravine which separates it from the 

 neighbouring but lower hill of Mon- 

 chagrin. This large ravine has its 

 origin in two great faults, which 

 run approximately N.E. and S.E. re- 

 spectively and meet near the mouth of 

 the ravine somewhat inland from the 

 position occupied by the wharf at San 

 Eernando. The hill itself is certainly 

 an anticline, as shown in the diagram- 

 section (p. 522) ; for on the northern 



^ The height of Naparima Hill is stated 

 in old documents at 670 feet. The Geolo- 

 gical Surrey put it at 590 feet. I have 

 failed to make it exceed 500 feet. On this 

 point see the remark of Orton (quoted in 

 Ann. & Mag. Nat. Hist. 4 ser. vol. xvi. p. 361) 

 that every successive measurement of the 

 Andes gives a reduced elevation. 





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