36 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4th Ser. 



Concerning this occurrence Conrad states that "The Eocene 

 period is unequivocally represented, by the beautifully perfect 

 shells from the Canada 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 connection of the Atlantic and 

 Pacific oceans during the Eocene period. The vast distance 

 between the two localities will account for the general dis- 

 tinction 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 'finger post' of the 

 Eocene, Cardita plauicosta, 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 hard 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." 



Gabb" in 1864 described many species which Captain Horn 

 collected from the vicinity of Caiiada de las Uvas and referred 

 the strata yielding this fauna to Division B of the Cretaceous. 

 Whitney^ in the next volume described the type locality of the 

 Tejon-Eocene as follows: 



"The Tejon group .... the division B of Palaeontology, vol. 

 1, is peculiar to California. It is found most extensively de- 

 veloped in the vicinity of Fort Tejon and about Martinez. 

 From the latter locality it forms an almost continuous belt in 

 the Coast Ranges to Marshs', 15 miles east of Mount Diablo, 

 where it sinks under the San Joaquin plain. It was also dis- 



^ Gabb, Wm., Geology of California, Palaeontology, vol. 1, 1864. 

 ' Whitney, J. D., Geology of California, Palaeontology, vol. 2, p. 19 of preface, 

 1869. 



