. Soil physics and management. Fig. 32.—Front of Chenega Glacier compared with Washington Monument, 550 feet high. (Lawrence Martin.). Fig. 33.—Very stony and gravelly phase of glacial drift near Whitewater, Wisconsin. (King.) 41 42 SOIL PHYSICS AND MANAGEMENT from three centers of accumulation in Canada. The northwesternhalf of Europe was covered at the same time. Vast quantities ofmaterial of all sizes and all kinds of rocks were transported anddeposited when the ice melted^ leaving a mantle of boulder clay,drift, or till, varying from a few inches to several hundred feet inthickness. The av
. Soil physics and management. Fig. 32.—Front of Chenega Glacier compared with Washington Monument, 550 feet high. (Lawrence Martin.). Fig. 33.—Very stony and gravelly phase of glacial drift near Whitewater, Wisconsin. (King.) 41 42 SOIL PHYSICS AND MANAGEMENT from three centers of accumulation in Canada. The northwesternhalf of Europe was covered at the same time. Vast quantities ofmaterial of all sizes and all kinds of rocks were transported anddeposited when the ice melted^ leaving a mantle of boulder clay,drift, or till, varying from a few inches to several hundred feet inthickness. The average depth of the deposit for Illinois, accordingto Leverett,^ is about 115 feet. These glacial deposits constitute thematerial from which the soils were formed over a large area east andnorth of Illinois, but in the middle west a deposit of loess hasburied-the drift, producing soils of an entirely different character(Fig. 33). In glaciated Europe the same conditions exist in regardto soils.
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