The ice age in North America and its bearing upon the antiquity of man5th edwith many new maps and illus., enland rewritten to incorporate the facts that bring it up to date, with chapters on Lake Agassiz and the Probable cause of glaciation . Fig. 108.—Conglomerate bowlder found in Boone County, Kentucky. ^8ee te.\t.) completely around the eastern, northern, and western sides ofthe Kentucky peninsula formed by the great bend of theriver), the ice came down to the trough of the Ohio, andcrossed it so as completely to choke the channel, and form aglacial dam high enough to raise the level of th
The ice age in North America and its bearing upon the antiquity of man5th edwith many new maps and illus., enland rewritten to incorporate the facts that bring it up to date, with chapters on Lake Agassiz and the Probable cause of glaciation . Fig. 108.—Conglomerate bowlder found in Boone County, Kentucky. ^8ee te.\t.) completely around the eastern, northern, and western sides ofthe Kentucky peninsula formed by the great bend of theriver), the ice came down to the trough of the Ohio, andcrossed it so as completely to choke the channel, and form aglacial dam high enough to raise the level of the water fivehundred and fifty feet—this being the height of the water-shed to the south. The consequences following are inter-esting to trace. The bottom (^f the Ohio River at Cincinnati is 432 feet. S 5 o _o O aB 370 THE ICE AGE IN NORTH AMERICA. above the sea-level. A dam of 568 feet would raise thewater in its rear to a height of 1,000 feet above the would produce a long, narrow lake, of the width of theeroded trough of the Ohio, submerge the site of Pittsburgto a depth of 300 feet, and make slack water up the Monon-gahela nearly to Grafton, W. Ya,, and up the Alleghany asfar as Oil City. All the tributaries of the Ohio would like-wise be filled to this level with the back-water. The lengthof this slack-water lake in the main valley, to its terminationu|) either the Alleghany or the Monongahela, was not farfrom one thousand miles. The conditions were also peculiarin this, that all the northern tributaries head within the south-ern margin of the ice-front, which lay at varying distances tothe north. Down these northern tributaries there must havepoured during the summer months immense torrents of waterto strand bowlder-laden icebergs on the summits of such highhills as
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Keywords: ., bookauthoruphamwarren18501934, bookcentury1900, bookdecade1910
