sea id i Aah Basa Gl a i a a ie ee x 
B, Silliman on the Mining Districts of Arizona. 297 
Indians, from whom, by purchase or treaty they can soon be ob- 
tained. In respect to agricultural capacities this region is more 
favored than most of the mining districts of Nevada, and may be 
Was general and simultaneous for this region, seems almost cer- 
tain from the fact of the parallelism of the east and west lodes, 
4% well as from their mineralogical and metallurgical identity, 
So far as present observation and exploration justify an opinion. 
A second period of eruption a to be clearly indica 
by the existence of the second ¢ 
hamely, the calcareous lodes, whose main course is northwest 
tirely unlike those of the east-and-west lodes. There is evidence 
Iso in this district, as well as in the country at large, oe 
given dino aaeel 11 lodes. This evidence is seen in 
Am. Jour. Sci—Szconp Serres, Vou. XLI, No. 123,—Mar, 1866, 
38 
