Abstract
This paper documents age assignments for two widely separated and isolated northern California Franciscan formation limestone pods that have not previously been reported in published literature. These assignments, the first definite early Eocene fauna thus far recognized, and the most northeasterly occurrence of a Late Cretaceous Cenomanian stage fauna, were made by examining planktonic Foraminifera in thin sections. In northern California, the Franciscan is divided into three broad northwest-trending belts: an eastern metamorphic belt, a central melange belt, and a western and youngest coastal belt. The occurrences of Rotalipora appenninica, R. cushmani, Praeglobotruncana stephani, and P. stephani var. turbinata in a limestone pod in the melange belt, about 10 mi (16 km) east of Covelo, indicate a Late Cretaceous (Cenomanian) age. Other limestone blocks in the same area contain Late Jurassic (Tithonian) megafossils. In the coastal belt, a limestone pod from an abandoned quicksilver mine about 6 mi (10 km) north of Branscomb includes Globorotalia subbotinae = G. rex, G. aragonensis, G. caucasica? and G. pseudotopilensis, indicative of an early Eocene age. End_of_Article - Last_Page 1685------------
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