Identifier: iceageinnorthame00wriguoft (find matches)
Title: The ice age in North America and its bearing upon the antiquity of man. 5th ed. with many new maps and illus., enl. and rewritten to incorporate the facts that bring it up to date, with chapters on Lake Agassiz and the Probable cause of glaciation
Year: 1911 (1910s)
Authors: Wright, G. Frederick (George Frederick), 1838-1921 Upham, Warren, 1850-1934
Subjects: Glacial epoch Glaciers
Publisher: Oberlin, Ohio Bibliotheca Sacra Co
Contributing Library: Gerstein - University of Toronto
Digitizing Sponsor: MSN

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and a half wide. These features of greater age, pertaining to the bluffs ofthe Mississippi below Fort Snelling, are seen in the old rock-bluffs of the river above the mouth of Bassetts Creek as far asto Shingle Creek. The rock there is deeply changed in color,and is hid by the drift, and the bluffs, as left by the more an-cient river, are far apart, the old gorge being three or fourtimes as wide as that between the falls and Fort Snelling.These rock-bluffs, consisting of the same limestone as thatwhich at the falls is below the water, here rise from thirty toforty feet above the river, and are buried under loam, or underdrift and loam. This part of the old valley continues south-wardly, by way of Bassetts Creek (below its last turn), acrossthe western suburbs of Minneapolis, through the valleys occu- I THJ^ DATE OF THE GLACIAL FhlilOU. 555 pied by Lakes Calhouu and Harriet, and joins the Minnesotaat some point above Fort Snelling, the precise locality being TxVLLS IN 11580mLS Df 1680
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Fie. 142.—Map of Mississippi River from Fort Snellint; to Minneapolis and the vicinity,showinj? the extent of the recession of the Falls of St. Anthony since the great Iceage. Notice the greater breadth of the valley of the Minnesota River as described inthe text. hid by a subsequent deposit of drift, Tt was eat down intothe St. Peter sandstone over one hundred feet at least, a«shown by the well at the Sumner school-house, and about two 556 THE ICE AGE IN NORTH AMERICA. hundred and seventy-five feet, as shown by the deep well at theLakewood Cemetery. This would show that probably the an-cient valley of the Minnesota where it passes Fort Snelling,and all the way through Ramsey county and below, has beentilled more than two hundred feet by drift that originatedsince the excavation of the gorge. This supposition is borneout by all borings that have been made between the rock-bluffsat lower points, as at West St. Paul and at Lake City. Suchexcavation is not found in the river-gorge bet

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