Excerpt from Contributions to Economic Geology (Short Papers and Preliminary Reports), 1921, Vol. 2: Mineral Fuels The Survey's Contributions to economic geology have been pub lished annually since 1902. In 1906 the increase in the number of papers coming under this classification made it necessary to divide the contributions into two parts, one including papers on metals and nonmetals except fuels and the other including papers on mineral fuels. In 1915 the year included in the title was changed from the year in which the field work reported in these papers was done to the year Of publication, and in consequence there was no volume entitled Contributions to economic geology, The subj oined table gives a summary of these bulletins. United States Geological Survey Contributions to economic geology. 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.