30 H. Doc. 129. 



ARTICLE IV. 



NOTICE OF THE FOSSIL FISHES FOUND IN CALIFORNIA BY WILLIAM P. 

 BLAKE, GEOLOGIST OF THE UNITED STATES PACIFIC RAILROAD SUR- 

 VEY UNDER THE COMMAND OF LIEUTENANT R. S. WILLIAMSON, 

 UNITED STATES TOPOGRAPHICAL ENGINEERS; BY LOUIS AGASSIZ. 



Most of the fossil remains of fishes placed in my hands by Mr. 

 Blake for examination and identification belong to the family of 

 sharks, one belongs to that of skates, and another is remotely allied 

 to the family of mackerels. No fossil sharks' teeth having been found 

 west of the Rocky mountains before, the discovery by Mr. Blake of a 

 variety of species belonging to several genera of the family of sharks 

 constitutes one of the most interesting additions to our knowledge 

 that could have been obtained from that quarter, and the importance 

 of these fossils to science is further enhanced by the peculiar relations 

 they bear to similar fossils found in the Atlantic States and in Europe 

 and to the sharks now living along the shores of the old and of the 

 new world. 



ECHINORHINUS, Blainv. 



1. E. BLAKEI, Agassiz, pi. , fig. . The most interesting and import- 

 ant discovery since the publication of the Poissons Fossiles is that of 

 the tooth of the genus Echinorhinus, in the tertiary deposits of Ocoya 

 creek, (Pose creek,) at the western base of the Sierra Nevada, Cali- 

 fornia. The genus Echinorhinus was founded by Blainville for the 

 Squalus spinosus of Linnaeus, the only species, of the genus thus far 

 known which inhabits the Mediterranean and the European and 

 African coasts of the Atlantic. 



I figured the teeth of the same genus under the name of Goniodus 

 for the same species, (see Poissons Fossiles, vol. iii, p. 94, pi. E, fig. 

 13,) so that this name must give way to the Echinorhinus of Blain- 

 ville. 



The discovery of a fossil species of this genus in the tertiaries of 

 the western slope of the Sierra Nevada is not only important as carry- 

 ing back this curious type of sharks to a period older than ours, but 

 also in disclosing the existence upon the American continent of types 

 in a fossil state known in the old world only among the living. The 

 fossil species of Echinorhinus differs from the living, having the main 

 point of the tooth more prominent, and at the same time shorter, an 

 appearance which arises from the less prominence of the marginal 

 denticles. This difference may be distinctly seen by comparing the 

 figures pi. , with those of the living species given in Poissons Fos- 

 siles, pi. E, fig. 13. 



SCYMNUS, Cue. 



2. s. OCCIDENTALIS, Agassiz. The few species upon which Cuvier 

 founded the genus Scymnus have been of late subdivided by M Ciller 

 and Henle into two genera : Scymnus proper, and Lcemargus ; all of 



