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University of California Publications in Geology [Vol. 10 



The mammal forms now known from the Rattlesnake formation 

 are the following : 10 



Rattlesnake Fauna 



Camivora 



?Canis davisi Merriam 



Amphieyon, near amnicola Matthew and Cook 

 Mustela, sp. a 

 Mustela, sp. b 

 Felis, large sp. 



Indaretos? oregonensis Merriam, Stock, and Moody 

 Edentata 



Megalonyehid, gen. and sp. indet. 

 Rhinocerotidae 



?Teleoceras fossiger (Cope) 

 Equidae 



Hipparion sinclairii Wortman 



Hipparion, near occidentale Leidy 



Hipparion, near anthonyi Merriam 



Pliohippus, near fairbanksi Merriam 



Pliohippus speetans (Cope) 

 Suidae 



Prosthennops, sp. 

 Camelidae 



Alticamelus altus (Marsh) 



Pliauchenia, sp. 



Procamelus, sp. 

 Antelojunae 



Sphenophalos, near nevadanus Merriam 



Ilingoceros?, sp. 

 Mastodontinae 



Tetrabelodon ?, sp. 

 Rodentia 



Lepus?, sp. 



Dipoides?, sp. 



Of the Rattlesnake horses, the best represented Pliohippus forms 

 are much like those in the Pliohippus coalingensis zone of the Etche- 

 goin, in the Thousand Creek, and in the Ricardo. The Hipparion 

 species are like forms of the Thousand Creek and show some resem- 

 blance to a species from the Hipparion zone of the Pacific Coast 

 province. 



The Rattlesnake antelopes resemble those of the Thousand Creek 

 fauna. 



The Thousand Creek fauna is known from extensive exposures in 

 the valley of Thousand Creek at the extreme northern border of 

 Nevada. The stratigraphic relations of the Thousand Creek formation 

 are unfortunately not as yet fully known, but there is every reason 



10 From unpublished manuscript of Merriam, Stock, and Moody. 



