Excerpt from Placer Gold Deposits of New Mexico: A Catalog of Location, Geology, and Production, With Lists of Annotated References Pertaining to the Placer DistrictsMost placer gold deposits in New Mexico are derived from gold-bearing mineralized areas in Tertiary intrusive rocks, and occur in gravels of alluvial fans, gulches, and rivers adjacent to the source. A few deposits are derived from gold-bearing Pre cambrian crystalline or Tertiary volcanic rocks. Most of the major placer districts were discovered and extensively worked between 1828 and 1880, in later years, large-scale dredging operations were successful at a few localities, while intermittent activity continued at most districts.About the PublisherForgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.comThis 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.