412 University of California Publications in Geology [Vol. 9 



inter andesitic age. In the locality figured in PL 11 B, p. 72, of his 

 ' ' Tertiary Gravels of the Sierra Nevada, ' ' the gravels contain abund- 

 ant boulders of andesite as well as rhyolitic fragments. Turner 59 

 describes this locality as follows : ' ' This conglomerate consists of a 

 variety of pebbles — quartzite, mica schist, quartz-porphyrite, grani- 

 toid rocks, andesite, and rhyolite being represented." 



From Lindgren's excellent statement and the conditions described 

 above at Oroville Table Mountain it is evident that a correlation 

 between the Tertiary gravels and the lone is made possible. Lind- 

 gren recognizes the following divisions in the Tertiary gravels and 

 the volcanic formations associated with them : a, Deep gravels of 

 Eocene age ; b, bench gravels ; c, rhyolitic tuffs and interrhyolitic 

 channel ; andesitic tuffs and intervolcanic channel. The accompany- 

 ing figure copied from Lindgren's paper shows the relations of these 

 deposits graphically (see figure 7). A fourfold division of the 



Fig. 7. Schematic representation of the four principal epochs of Tertiary 

 gravels in the Sierra Navada. a. Deep gravels (Eocene); h, bench gravels 

 (Eocene); c, rhyolitic tuffs and interrhyolitic channel; d, andesitic tuffs and 

 intervolcanic channel. (Adapted from Lindgren.) 



lone is better for the purpose of correlation than Turner's threefold 

 division. The lowermost division in the type locality of the lone is 

 (1) the sand and gravel member in the bottom of the deep basin near 

 lone, 500 to 600 feet; (2) clays derived from rhyolite with inter- 

 bedded lignite, 100 to 200 feet; (3) white and red coarse-grained 

 sandstone with scales of alunite, 25 to 75 feet; (4) rhyolite and its 

 clay derivatives ("clay rock" of Turner), to 50 feet. Andesitic 

 tuffs or their equivalents, the Neocene shore gravels, are sometimes 

 found resting upon the third or the fourth member of the lone. The 

 probable relationship between the lowermost member of this sequence 

 and the deep gravels was indicated by Lindgren: "Near Valley 

 Springs the lone attains elevations of 1000 feet, and its highest mem- 

 bers are probably several hundred feet above the deepest gravels of 



so Turner, H. W., Rocks of the Sierra Nevada, Fourteenth Annual Report, 

 U. S. Geological Survey, p. 468, 1894. 



