XIV PREFACE. 



relations with the formation in Europe have not yet been 

 fully determined, though it is on the horizon of either the 

 Upper or Lower Chalk, and may probably prove to be the 

 equivalent of both. It is extensively represented in Shasta 

 and Butte counties, and in the foot-hills of the Sierra Nevada 

 as far south as Folsom, occurring also on the eastern face of 

 the Coast Ranges bordering the Sacramento Valley, at Mar 

 tinez, and again in Orestimba Canon, in Stanislaus County. 

 It includes all of the known Cretaceous of Oregon and of 

 the extreme northern portion of California, and is the coal- 

 bearing formation of Vancouver's Island. 



4th. The Shasta Group is a provisional name, proposed to 

 include a series of beds of different ages, but which, from our 

 imperfect knowledge of the subject, cannot yet be separated; 

 it includes all below the Chico Group. It contains fossils, 

 seemingly representing ages from the Gault to the Neocom- 

 ien, inclusive, and is found principally in the mountains west 

 and northwest of the Sacramento Valley. Two or three of 

 its characteristic fossils have been found in the vicinity of 

 Monte Diablo, and one of the same species has been sent 

 from Washington Territory, east of Puget Sound. Few, or 

 none, of its fossils are known to extend upwards into the 

 Chico Group. 



J. D. WHITNEY. 



CAMBRIDGE, MASS., February, 1869. 



NOTE. Section 1, Part 1, was issued in February, 1866 ; the remainder of this 

 volume was laid before the Philadelphia Academy, in a printed form, in December, 

 1868. 



