. Bulletin of the Department of Geology. Geology. 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. Turner59 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 ; From Lindgren's excellent statement and the conditions described above at Orovill
. Bulletin of the Department of Geology. Geology. 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. Turner59 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 ; 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), 0 to 50 feet. Andesitic tuffs or their equivalents, the Neocene shore gravels, are sometimes found resting upon the third or the fourth member
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