442 University of California Publications in Geology [Vol. 11 



The Barstow formation will be recognized as a division of the 

 Rosamond Series if the Barstow syncline corresponds to the type 

 section of the Rosamond at Rosamond station, as has been assumed 

 by Hershey and by Baker. As yet it seems difficult to make certain 

 of correlation between the Barstow syncline and the type Rosamond 

 section, as palaeontologic evidence is lacking at Rosamond. If the 

 Barstow formation is considered as a member of the Rosamond, it is 

 presumably a late member of the series. 



The section of deposits at Red Rock Canon was first described 

 by G. K. Gilbert, 10 who gave the essential features of the stratigraphie 

 succession and referred to the exposures as the Red Rock Canon beds. 

 More than twenty years later, in 1896, H. W. Fairbanks 11 gave a 

 further description of the section at Red Rock Canon furnishing esti- 

 mates of thickness, degree of deformation, and extent of distribution 

 of the beds. Following the usage of Gilbert, Fairbanks r»&watl +^ 

 the section as the Red Rock Canon beds. 



In a paper reviewing the Eocene of North America m 1900, J. H. 

 Smith 12 used the heading "Mohave Formation" for a paragraph 

 which, with the exception of a little more than one line, consisted of a 

 quotation from Fairbank's description of the sediments in the region 

 of El Paso Range and Black Mountain. Smith's reference was 

 directed especially toward a portion of the section near Black Moun- 

 tain from which Fairbanks reported leaves determined by F. H. 

 Knowlton as Eocene. Recent investigation of the area in which the 

 leaves were found has not made clear the stratigraphie relations of 

 the plant horizon, and it is possible that the lowest beds at Black 

 Mountain from which the reported Eocene leaves were obtained may 

 actually represent an Eocene horizon. 



In discussing the Cenozoic history of the Mohave Desert in 1911 

 C. L. Baker 13 referred the Red Rock Canon section to the Rosamond 

 Series. In his paper 14 on the Physiography and Structure of the 

 Western El Paso Range Baker continued use of the term Rosamond 

 Series for the Red Rock Canon section. 



Following the discovery that the fauna from the beds in Red Rock 

 Canon is sharply distinct from that in the Barstow section, the writer 



10 Geographical and Geological Explorations West of the 100th Meridian, 

 pp. 142-143, 1875. 



11 Amer. Geol., vol. 17, pp. 68-69, 1896. 



12 Jour. Geol., vol. 8, pp. 455-456, 1900. 



is Ilniv. Calif. Publ., Bull. Dept. Geol., vol. 6, p. 354, 1911. 



1* Univ. Calif. Publ., Bull. Dept. Geol., vol. 7, pp. 117-142, 1912. 



