Excerpt from Analyses of Rocks From the Laboratory of the United States Geological Survey, 1880-1899 Quite naturally, on account of the activity of the petrographers, the dominant feature of the laboratory work has been the analysis of rocks. These have been studied in great numbers and in the most thorough way. The results have appeared in widely scattered publications, official reports, monographs, bulletins, American and foreign journals, and so on. The object of this bulletin is to bring together this valu able material, together with such bibliographic and petrographic data as seems to be necessary in order to identify the specimens and to facili tate chemical discussion. Analyses of minerals have been included only when related to petrographic studies, appearing then in connec tion with the rocks to which they belong. Meteorites, of which twenty-nine have been analyzed, are brought into the work on account of their petrographic relations; and the groups of clays and soils have been admitted because of the bearing of these substances upon the studyof slates and shales. The actual number of'analyses given in the bulletin is as follows. 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.