Abstract
ANDALUSITE IN CALIFORNIAN EOCENE SEDIMENTS
BY VICTOR T. ALLEN
Californian Chico Cretaceous sandstones near Folsom and Pentz and at the type locality on Chico Creek lack pink andalusite. The overlying Eocene Ione sandstones and correlated auriferous gravels contain pink andalusite derived from the bedrock series of the Sierra Nevada. If these Cretaceous and Eocene sediments were both derived from the same source, it appears that contact aureoles around Sierran intrusions with a grade of metamorphism sufficiently high to contain andalusite were not exposed by erosion until Eocene time. Under the Great Valley at several localities a similar limitation of andalusite to the Eocene and younger sediments has been found. It is suggested that careful watch be kept by all investigators to check the possibility of using andalusite to separate Cretaceous from Eocene sediments in California. (Geological Society project.)
JOINT PATTERNS IN HIGHLY FOLDED AND CRYSTALLINE ROCKS OF THE NORTHERN NEW . . .
