NATURAL SCIENCES OP PHILADELPHIA. 199 



localities of the former, and nine of the latter, most of which he 

 has visited. 



The fragment of a tusk, from Stanislaus Co., referred to Mastodon 

 Shepai-di, Dr. Yates found imbedded in the blutf of a hill about 

 ten feet above the bed of a creek. The hill, upwards of a hundred 

 feet in height, is one of the tertiary hills mentioned in Wliitney's 

 Geological Report, as being scattered over the plain of San 

 Joaquin, at the base of the foot-hills of the Sierra Xevada. 



The remains of the Mastodon of Contra-Costa Co. were obtained 

 from the rock at the base of one of the rounded hills, of tertiary 

 age, mentioned in Whitney's Report, pp. 31, 32, near the edge of 

 the San Joaquin Plains, which skirt along the foot-hills of Monte 

 Diablo. 



A small photograph, accompanying Dr. Yates' letter, represents 

 a much mutilated lower jaw, without the ascending portions poste- 

 riorly, and with straight tusks projecting with an upward direc- 

 tion. The tusks appear to be quite as long as the jaw has been in 

 its complete state. No details of character are given in relation 

 to the specimen. 



Note on Anchitherium. — Prof Leidy also exhibited a specimen 

 recently received from Prof. Hayden, who discovered it on the 

 head waters of the Jefferson Fork of the Missouri River. It 

 consists of a portion of the lower jaw, apparently of a species of 

 Anchitherium, larger than A. Bairdi, and relating in size to a 

 mutilated molar, from John Daj^'s River, Oregon, referred to A. 

 Gondoni (Pr. 1870, 112), and may, perhaps, pertain to the same 

 species. 



On motion the following papers were ordered to be published: — 



1871.] 



