UNIVERSITY OF CALIFORNIA PUBLICATIONS 

 Bulletin of the Department of Geology 



Vol. 3, No. n, pp. 243=248. ANDREW C. LAWSON, Editor 



A NEW TORTOISE FROM THE AURIFEROUS 

 GRAVELS OF CALIFORNIA. 



BY 



W. J. Sinclair. 



So few vertebrate remains are known from the auriferous 

 gravels of the Sierra Nevada, that the discovery of any Avell pre- 

 served material helps considerably in the attempt to make an 

 exact determination of the age of these deposits. Testudinates 

 from the gravels are unknown in palaeontological literature, but 

 accounts of the finding of " turtles " in the placer mines are still 

 remembered in the mining region. Particular interest attaches 

 to the specimen here described not only on account of its superior 

 state of preservation, but because its relation to the gravels has 

 been determined by a careful examination of the locality where 

 it was found. This tortoise is from gravels of the rhyolitic 

 epoch, about two miles below Vallecito, Calaveras County, on 

 the Parrott's Ferry road. It was discovered by Messrs. Sloan 

 and Rudorf, the proprietors of the "Old Stiff" gravel mine, on 

 Balaklava Hill. The gravel in which the specimen was found 

 contains small fragments of rhyolite tuff, but no pebbles of the 

 later volcanic rocks of the Sierra Nevada. The gravels are 

 overlain by a white rhyolite tuff, exposed at the top of the high 

 bank above the mine pit. The tuffs are overlain by a gravel con- 

 taining abundant andesite pebbles, and the section is capped by 

 a sheet of augite-latite, a part of the Tuolumne Table Mountain 

 flow described by Dr. Ransome.* The remains of the animal 

 were found in a stratum of gravel mixed with sand and fine tuff 

 particles, lying from ten to fifteen feet above the bedrock of the 



* Some lava flows of the western slope of the Sierra Nevada, California. 

 U. S. G. S. Bulletin No. 8i). 



