3 

 Vaqueros in Ellsmere Canyon. 



In the same bulletin Arnold gives a list of fossils from 

 Ellsmere Canyon which he calls of Middle Fernando age. 



In 1910 R. B. Mo ran made a collection of fossils in Ells:nere 

 Canyon. In a paper given "before the Palaeontological Society, he 

 considered the fauna as of Monterey age, because of certain Lower 

 Niocene forms which he found. 



STRATIGRAPHY. 



The chief formation of the San Gabriel Range is the San Gabriel 



Granite, a complex of granitic rocks and schists which makes up the 



4 

 whole central part of the range. Arnold divides the San Gabriel 



Arnold, R. and Strong, A.M., Some Crystalline Rocks of the San 

 Gabriel Mountains, Cal. Bull. Geol, Soc. Am., vol. 16, 1905,p.l88-9 



range into a southern Sierra Madre, and the main San Gabriel. He 



says "The Sierra Madre Range consists essentially of granddiorites 





 and gneisses, with more acid areas in which the country rock is 



quartz-monzonite. The character of the rocks of the mountain area 

 north of the Sierra Madres is considerably different from that of 

 the latter. True biotite and rather coarse grained granodiorite, 

 decidedly different in appearance from that of the southern range, 

 are found in the northern mass." The west end of the San Gabriel 

 Range is chiefly granodiorite, with gneiss and other schists. 



The Fernando formation of this area is not less than three to 

 four thousand feet thick, and was laid down upon an eroded surface 

 of the San Gabriel Granite. The upper surface of the granite is 

 generally somewhat decomposed. The basal ten to fifteen feet con- 

 sists of subangular to rounded fragments of granite, with comminuted 



