PROCEEDINGS 



OF THE 



WASHINGTON ACADEMY OF SCIENCES 

 Vol. VIII, pp. 405-406. February 13, 1907. 



AGE OF THE PRE-VOLCANIC AURIFEROUS 

 GRAVELS IN CALIFORNIA. 



By J. S. Diller. 



GENERAL STATEMENT. 



The age of the auriferous gravels of the Sierra Nevada in 

 California is generally given as late Miocene or Pliocene and is 

 based chiefly on fossil plants and a few animal forms. The 

 auriferous gravel period in all probability was a long one and 

 no considerable part of its flora has yet been connected directly 

 with its contemporaneous marine fauna of the same region. 



On physiographic and stratigraphic grounds and the general 

 relations of the Sierra Nevada to sedimentation, it has long been 

 supposed by some geologists that the oldest auriferous gravels, 

 the deep gravels of Lindgren, are probably Eocene, but the 

 evidence assigned is problematic rather then positive. 



EOCENE FLORA OF SOUTHWEST OREGON 



While studying the Eocene deposits of the Roseburg, Coos 

 Bay, and Riddles quadrangles in Oregon, fossil leaves were 

 found in the same strata with marine shells, thus affording an 

 opportunity definitely to connect the land flora with its contem- 

 poraneous marine fauna. 



The following list of ten species embraces the Eocene plants 

 identified by Dr. F. H. Knovvlton with more or less certainty 

 from a number of localities within the area noted above : 



Magnolia lanceolata Lesq. 



Magnolia californica ? Lesq. 



Laurus californica ? Lesq. 



Sabalites calif ornicus ? Lesq. 



Aralia whitneyi Lesq. 

 Proc. Wash. Acad. Sci., February, 1906. ( 405 ) 



