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Bulletin 35 
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Page 109 
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 fo.ssils of the compact 
limestone by Dr. vStevens, who was engaged at the gold 
mines of Venezuelan Guiana. He showed me a piece of 
limestone containing small gastropods, like Murchisonia (J/. 
amia Billings), and small bivalves like Leptodomus. Dr. 
Stevens was aware that I had already discovered organisms 
in the cla}’ slates and calciferous .slates of the older series. 
Further search in the blue limestone re.sulted in mj* finding 
a shell differing .slighth' 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 any certaint)’ 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 Loxonema lincta Phill. Pal. Foss). Suppos- 
ing my ideas of the resemblances of these fo.ssils to be some- 
where near the truth, the age of the compact limestone 
might be Devonian or Carboniferous. The corals found 
a.ssociated with the .shells are of a ma.ssive 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 
