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Excerpt from Geology of Scott County, Iowa, and Rock Island County, Illinois, and the Adjacent Territory The Wapsipinecon River has abraded its channel in the Niagara from Township 86, in Linn County, to the Mississippi River. It has asserted its claim to the old eroded valley that was denuded previous to the deposition of the Water-lime group. The same seems to be the case with the Maquoketa. This ancient erosion has brought many different members of the Niagara rocks to the surface, which is evidenced by the numerous outliers of the Water lime group reposing upon them. There is a hiatus in the Upper Silurian rocks of Iowa. "The Onondaga Salt group in New York succeeds the Niagara limestone with a thickness of one thousand feet or more" (Hall's Iowa, p. 40) and the Guelph of Canada, with its one hundred and sixty fee (Logan's Canada, p. 338), are entirely wanting in Iowa. It would appear that all the time these twelve hundred feet of sedimentary strata were being deposited, the Niagara rocks of Iowa were land and subjected to denuding agencies. The Niagara limestones near De Witt are hard, rough, and horizontally disposed. At Rothstein's Mill they are soft, shaly, and contain several species of Rhynchonellas. On the Wapsipinecon near Dixon, they are heavy-bedded, of medium hardness, and are horizontally disposed. Two miles south-east from the latter place, a an altitude probably of one hundred feet, they are thin-bedded of medium hardness, horizontally disposed, and capped with a partially eroded strata of the Water-lime group. There is a lime-kiln at this place. The upper strata is not used for burning. A short distance east of this place the limestones are hard, rough, and heavy-bedded. At Big Rock the creek has made a deep cut into hard, even-bedded horizontal limestones. At Massillon the outcrop of the Niagara is a soft and shaly mass of Crinoid joints, with cast of Cyathocrinus. At Oxford Junction, on the slope, the outcrop is filled with casts of Pentamerus oblongus. Higher up on this slope, the farmers have to drill their wells eighty to one hundred feet, to a level with the water in the Wapsipinecon. The rock is soft and porous. This is in Township 83 north, Range 2 west. Continuing up this slope for half a mile, a hard, compact silicate of limestone outcrops. They are even-bedded in strata of from eighteen to thirty inches. They extend west and north, and cover an area of nearly twenty square miles. 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.