Geology and Water Resources of a Portion of Southeastern South Dakota (Classic Reprint)

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Excerpt from Geology and Water Resources of a Portion of Southeastern South DakotaIn this region there are no traces of Paleozoic formations nor of the Triassic and Jurassic of Mesozoic time. The surface of the Sioux quartzite shows marks of long erosion at an elevation of several hun dred feet above sea level. The nearest occurrence of Paleozoic rock that has been discovered is in the borings at Ponca, Nebraska, and Sioux City, Iowa. While the mountain masses of the Appalachian region and the extensive coal fields of the eastern part of the Missis sippi Valley were forming this area was probably a barren mountain ous region. It is possible that soils and vegetations'which may have extended over it were removed by the advance of the sea during Cretaceous time. At any rate, no traces of soil are now found upon'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.