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Bulletin 35 



Page log 



may turn out to be newer paleozoic or even older secondary. 

 This is perhaps speaking rather widely ; but the state of the 

 fossils found so far does not allow of a more definite state- 

 ment. Professor Tate is of opinion that the whole series is 



jurassic. 



My attention was first called to the fossils of the compact 

 limestone by Dr. Stevens, who was engaged at the gold 

 mines of Venezuelan Guiana. He showed me a piece of 

 limestone containing small gastropods, like Murchisonia (M. 

 anna Billings), and small bivalves like Leptodomus. Dr. 

 Stevens was aware that I had already discovered organisms 

 in the clay slates and calciferous slates of the older series. 

 Further search in the blue limestone resulted in my finding 

 a shell differing slightly from Dr. Steven's specimens, and 

 more resembling another North American species of Murchi- 

 sonia {M. linearis Billings). Lately I have discovered at 

 the Cotoras (at Five Islands) a number of specimens of a 

 Turritella-like shell, which, however, I am not able to refer 

 with an}^ certainty to Murchisonia, although there is a possi- 

 bility that it may belong to that or an allied genus. There 

 was, I thought, a resemblance between the specimens and 

 some of the narrow forms of Nerinea, but I was unable to 

 demonstrate either a hollow axis or folds on the columella. 

 Several specimens also occurred of another and much smaller 

 gastropod (like Loxonema lincta Phill. Pal. Foss). Suppos- 

 ing my ideas of the resemblances of these fossils to be some- 

 where near the truth, the age of the compact limestone 

 might be Devonian or Carboniferous. The corals found 

 associated with the shells are of a massive kind, but I could 

 not detach a fragment. I have been told of the discovery 

 of a heterocircal fish in these rocks, the specimen having 



