Whitbeck, R. H., 1871-1939 (Ray Hughes) / The geography of the Fox-Winnebago valley
Chapter II. The origin and physical features of the Fox-Winnebago Valley, pp. 7-12 PDF (1.9 MB)
THE ORIGIN AND PHYSICAL FEATURES 9 But the Valley of Lake Winnebago and the Lower Fox is not alone due to erosion by a river. It is altogether probable that from an early geological period, a river has flowed in this valley- in fact eroded the valley in the weaker rocks which have already been referred to. Even before the Glacial Period, the hard Niagara limestone stood out as a ridge or cliff. At that time there was no Lake Michigan and, of course, no Green Bay, although there probably was a valley occupied by a river* where Lake Michigan now is, and a river probably flowed in the present Fox-Winnebago Valley. At a comparatively recent period, as geology counts time, the climate of North America became so cold that great glaciers spread over the northern part of the continent and an enormous body of ice crept southward from Canada as far as the present Ohio and Missouri rivers; this was the Ice Age or Glacial Period. It was made up of several cold epochs and between these were warmer ones during which the glacial ice melted back to the north, only to return long afterward with the return of another cold epoch. Each of these alternating periods of warm and cold climate was tens of thousands of years in duration; it is quite possible that we are now living in one of the warm epochs and that this may be followed, thousands of years hence, by another return of the glacial ice, another Ice Age. THE GLACIATION OF THE VALLEY The mass of slowly-moving ice which spread over northern and eastern Wisconsin had its center of supply in Labrador, and the front of the glacier was in the form of great lobes. If a part of the ice flowed in a valley which extended in the same general direction as th e was moving, then that part of the glacier was able to move more freely, and a lobe of ice pushed forward a little more than it did where uplands or ridges retarded it. Thus, lobes of ice developed in certain valleys and gave the front of the glacier a lobate shape. (Fig. 2). It is now possible to discover where these lobes were by the great loops of terminal moraine, or ranges of rounded hillocks, which were built of the debris transported by the ice and heaped up along its margin as it * ~~melted. A good reason for believing that valleys existed in the Lake l Michigan and Green Bay depressions before the coming of the wgaciers is the fact thatwre b the front oh glacier in eastern Win *It ur as ted that this river probably loed southarld iS Martin, Lene, Te P| uicslGeopaphg of Wiscnsin. Bull. XXXVI. Wis. Geol. & Nat. Hist. Survey.
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