EOCENE ANAUXITE CLAYS AND SANDS IN THE COAST RANGE OF CALIFORNIA
BY VICTOR T. ALLEN
Eocene anauxite clays and sands occur at Tesla, 24 miles southeast of Mt. Diablo, and at Brentwood, 14 miles northeast of Mt. Diablo. In places clays and sands with an Ione mineral assemblage are interfingered with biotite sands from another source, in part of Coast Range derivation. On the basis of fossils examined by Bruce L. Clark the Tesla occurrence is assigned to the Capay division and the two horizons at Brentwood to the Meganos D and the Domengine divisions of the Eocene. The type Ione in the Sierra Nevada foothills is now considered Capay. The Capay at its type locality in the Coast Range lacks typical Ione minerals, which are present in the Potrero Hills near Suisun and at a depth of about 4500 feet at Rio Vista, within 35 miles of known Ione . . .