Book excerpt: Excerpt from The Mineralogy of Arizona It is well known to students of mineralogy that the greater num ber of interesting minerals are found at some depth below the surface in regions where the destructive effect of erosion and the decomposing action of meteoric water are not active and hence can be reached only by expensive exploitation rarely undertaken ex cept when compensation is hoped for in the possible discovery of the precious or useful metals. Arizona is attracting considerable attention on account of its unusual mineral resources, and its mountains and cafions are filled with excavations which are evi dences of the enthusiasm with which the search is carried on. Thus formations are penetrated and minerals exposed to view which, lacking this incentive, would never have been discovered. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.