Reports of explorations and surveys, to ascertain the most practicable and economical route for a railroad from the Mississippi River to the Pacific Ocean: Vol. 5, Pt. 2

APPENDIX.
divaricala, and both, in their markings, resemble N. cobbodii of the English Miocene. JIacra
Diegoana is nearly related to the Oregon M. albaria.
The Eocene period is unequivocally represented by the beautifully perfect shells from the
Cainada de las Uvas, which, though not found in situ, are evidently derived from strata occurring on the Pacific slope of the Sierra Nevada. This is very remarkable, inasmuch as three
species correspond with forms of Claiborne, Alabama, and seem to indicate a connexion of the
Atlantic and Pacific oceans during the Eocene period. The vast distance between the two localities will account for the general distinction of species, and it was, indeed, an unexpected
result to find any identical. If I had imagined any eastern species to occur in California, it
would have been the very one which does occur, and, apparently, in abundance, that "fingerpost" of the Eocene, Cardita planicosta, a fossil of the Paris basin, and also abundant in Maryland, Virginia, and Alabama. This species originated and perished in the Eocene period, and
is so widely distributed that it may be regarded as the most characteristic fossil of its era. As
the boulder from which these shells were derived was quite small, and yet furnished thirteen
species, when it shall be investigated in situ, doubtless a great many other forms will be obtained, and very likely some with which we are already familiar in eastern localities. Although
the rock is a very hardcl sandstone, the shells may be exposed in great perfection by careful
management, and we look forward with great interest to their further development, and to the
discovery of the rock in situ.
Respectfully, yours, &c.,
T. A. CONRAD.
WM. P. BLAKE, Geologist of the United States
Pacific 2ailload Survey in Calfornia.
CATALOGUE.
I. EOCENE.
No. Name. Locality.
Cardium linteum, (nova species.) Con -
Dosinia alta, (nov. sp.) Con —------------------------------------------
MeretrixUvasana, (nov. sp.) Con --------------------------------------
- Californiana, (nov. sp.) Con —---------------------------------
Crassatella Uvasana, (nov. sp.) Con —----------------------------------
- alta, Con —-----------------------------------------------
Mytilus humerus, (nov. sp.) Con —-------------------------------------
Cardita planicosta —---------------------------------------------------
Natica cotites. Con —------------------------------------------------
gibbosa. Lea. —-----------------------------------------------
- --- alveata —----------------------------------------------------
Turritella Uvasana, (nov sp.) Con —-----------------------------------
Volutatithes Californiana, (nov. sp.) Con —-----------------------------
Busycon? Blakei, (nov. sp.) Con. —------------------------------------
Clavatula Ca]ifornica, (nov. sp.) Con —----------------------------------
318
No.
Locality.
Name.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Cailada de las Uvas ----------------
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