76 



ECONOMIC GEOLOGY 



FIG. 55. View of a portion of Mercur, Utah, and the Mercur mine. (By 

 permission of the Macmillan Company, from Ries' Economic Geology.) 



FIG. 56. Lowest bed of coarse and bouldery gold-bearing gravel at 

 Cherokee mine, Butte County, California. (After W. Lindgren, U. S. 

 Geological Survey.) 



