Excerpt from The Klondike Gold District, in the Yukon Valley, Canada: A Paper Read Before the Above Association A few words as to the meaning of these terms may be useful in this connection We regard the Laurentian as the oldest rocks known - the foundation of the rocky crust of the earth. A lower and an upper division may be recognised in various parts of their distribution, which is very wide, comprising most of the north - eastern portion of North America, including Greenland. The rocks of the lower division are ...
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Excerpt from The Klondike Gold District, in the Yukon Valley, Canada: A Paper Read Before the Above Association A few words as to the meaning of these terms may be useful in this connection We regard the Laurentian as the oldest rocks known - the foundation of the rocky crust of the earth. A lower and an upper division may be recognised in various parts of their distribution, which is very wide, comprising most of the north - eastern portion of North America, including Greenland. The rocks of the lower division are composed of only a few of the commonest minerals, quartz, and orthoclase being the principal ones, together with a smaller proportion of hornblende and a little biotite or phlogopite. Scattered small crystals of magnetite may be occasionally detected. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at ... 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.
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