Economic Geology of the Silverton Quadrangle - Originally Published in 1901 as USGS Bulletin 182 this publication is one of the rarest and most informative on the Geology, Mines and Ore Deposits of the Silverton Area in the San Juan Mountains of Colorado. All major mining districts covered along with over 100 mines discussed and may more prospects. Extensive information on the formation of the deposits. Now Back in print by Miningbooks.com