B. Silliman on the Mining Districts of Arizona. 307 
the silver veins of the San Francisco District are nearly east 
and west in direction. 
The granitic range in which the “Pride of the Pines” vein 
oceurs extends for at least fifty miles, in a line nearly north and 
through this ancient drift, I saw for two and a half miles a see- 
tion, averaging perbaps one hundred feet in depth, of the mass 
of one of these moles of glacier-like materials, chiefly angular 
fragments of granite, some of quite large dimensions, mixed with 
forcibly recalling those of unquestionably glacial origin jutting 
out upon the American Desert from the eastern escarpments of 
lington’s and the Palmyra districts. i 
ese Arizona mounds run southeast from the main mountain 
and hills, gives it a character entirely in contrast with the 
just noticed. These features are espec 
mountain of the ‘Castle Ridge’ on the traveller’s left, as he leaves 
