GEOLOGY. 253 



companies the description of a few of the fossils collected by 

 Clerence King, Esq., of the U. S. Geological Survey says : 



" The trilobites described from Eastern Nevada are decidedly 

 primordial types, and, so far as I know, the first fossils of that 

 age yet brought in from any locality west of the Black Hills. Mr. 

 King's collections also establish the fact that the rich silver mines 

 of the White Pine districts occur in Devonian rocks, though the 

 Carboniferous is also well developed there. The Devonian beds 

 of that district yet known by their fossils seem mainly to belong 

 to the upper part of that system. Mr. King, however, has a few 

 fossils from Pinon Station, Central Nevada, that appear to belong 

 to the horizon of the Upper Helderberg limestone of the New 

 York series. 



" The tertiary fossils from the region of Hot Spring Mountains, 

 Idaho, came- from an extensive and interesting fresh-water la- 

 custrine deposit, and are all distinct specifically, and some generi- 

 cally, from all the other tertiary fossils yet brought from the Far 

 West. Two of the species belong to the existing California genus 

 Carinifex, or some closely allied group, while another beautifully 

 sculptured species may possibly be a true Melania, and allied to 

 existing Asiatic forms. 



" It is an interesting fact that among all four fresh-water ter- 

 tiary shells from this distant internal part of the continent, neither 

 the beaks of the bivalves nor the apices of the spores of the uni- 

 valves are ever in the slightest degree eroded ; even the most deli- 

 cate markings on these parts being perfectly preserved, if not 

 broken by some accident. From this fact it may be inferred that 

 the waters of the lakes and streams of this region during the ter- 

 tiary epoch were more or less alkaline, as is the case with many 

 of those there at the present day." 



A Fossil Tooth from Table Mountain; by Professor W. P. 

 Blake.- The fossil tooth found by Mr. D. T. Hughes, 1,700ft. 

 under Table Mountain and 300 ft. below the surface, I have care- 

 fully examined and compared with specimens in the Smithsonian 

 Institution. It proves to be a back lower molar of an equine 

 animal of the genus Hipparion. or a closely allied genus. This 

 genus is one of the connecting links between the Palceotherium 

 and the horse. 



The specimen closely resembles a fossil in the Smithsonian 

 Museum from the pliocene formations of the Niobrara River in 

 Nebraska, not only in size, but in the foldings of the enamel, and 

 particularly in the posterior part of the tooth, but it differs enough 

 in several particulars to justify the belief that it is a distinct 

 species. This fossil is the first of the kind discovered west of the 

 Rocky Mountains. It adds to the list of the fauna antedating 

 Table Mountain, a list which includes the mammoth, the rhinoc- 

 eros, and an animal allied to the elk. I have believed that remains 

 of man were also found under the lava ; but upon this point, after 

 diligent inquiry, I am satisfied that the evidence is insufficient. 

 But we now add this fossil allied to Hipparion, and I regard it as 

 another indication that the Table Mountain beds are pliocene and 

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