Mining and Scientific Press, Vol. 93

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Excerpt from Mining and Scientific Press, Vol. 93: From July to December, 1906 In the original survey it was shown that the slopes of the Mosquito range, back of Leadville, consist of fault blocks successively uplifted toward the east along north and south striking faults, in which the sedimentary beds lie in shallow synclines, the faults themselves following the steeper limb of the anticline. Recent underground developments have shown that, while the main fault planes were correctly located, their displacement was often distributed on several planes, so that the beds to the west of each fault zone descended not with the even slope of a syncline, but in a series of steps. Depths below the surface of the basins, as determined on the syncline the ory, were in general correctly given in the successive cross-sections of the original map. In the ease of the block represented by the Down-town area, however, no shafts had penetrated the covering of glacial deposits, and, while a shallow syncline in the underlying limestones was assumed to exist. In this block as in the others, no facts were available from which the western limit of the syn clinal basin could be determined. The finding of ore in this area was primarily dependent upon whether the ore bearing limestones had been eroded off before the so-called lake beds were deposited, in other words, whether the mm of the rock-surface beneath these beds is greater than the dip of the limestones. 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.