Description
Excerpt from Lake Agassiz: A Chapter in Glacial Geology
The superficial material which''overlies the bed-rock with 111 this northern glaciated area has everywhere beeh ploughed up and worked over by the slowly moving ice-sheet, and at its disappearance was left in a deposit of, clay, sand, gravel and boulders, mixed in one confused mass, which 18 called till. Except in the valleys, as ''of the Mississippi at Minneapolis, where streams have assorted the''se materials and spread them in layers, the till forms the surface of nearly all of Minne sota, its thickness being from 50 to 250 feet. It is the Stony and gravelly clay, in which cellars and wells are dug; and it forms a sheet of such great extent and. Thickness that about half of the counties of western Minnesota contain no exposures of the underlying older rocks.
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.
The superficial material which''overlies the bed-rock with 111 this northern glaciated area has everywhere beeh ploughed up and worked over by the slowly moving ice-sheet, and at its disappearance was left in a deposit of, clay, sand, gravel and boulders, mixed in one confused mass, which 18 called till. Except in the valleys, as ''of the Mississippi at Minneapolis, where streams have assorted the''se materials and spread them in layers, the till forms the surface of nearly all of Minne sota, its thickness being from 50 to 250 feet. It is the Stony and gravelly clay, in which cellars and wells are dug; and it forms a sheet of such great extent and. Thickness that about half of the counties of western Minnesota contain no exposures of the underlying older rocks.
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.
Details
Publisher - Forgotten Books
Language - English
Hardback
Contributors
Author
Warren Upham
Published Date -
ISBN - 9780260458261
Dimensions - 22.9 x 15.2 x 0.2 cm
Page Count - 30
Paperback
Contributors
Author
Warren Upham
Published Date -
ISBN - 9781334497452
Dimensions - 22.9 x 15.2 x 0.2 cm
Page Count - 32
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