Encyclopædia Britannica, Ninth Edition/Wisconsin

WISCONSIN, one of the North-Eastern Central States of the American Union, has the parallel of 42° 30' N. lat. for its southern limit, Lake Michigan for its border on the E., Lake Superior on the N., and the Mississippi on the W. Michigan on the E., Minnesota and Iowa on the W., and Illinois on the S. are its neighbour States. Its area, exclusive of water surface, is estimated at 54,450 square miles. Its length from north to south is 300 miles, its breadth 250 miles; its lake shore-line exceeds 500 miles. Its surface contours are gentle and pleasing. The lower parts of the State lie about 600 feet above the sea, the highest summits about 1800 feet. Few peaks rise more than 400 feet above their bases, and abrupt elevations of more than 200 or 300 feet are not common except along the Mississippi. The State is merely a swell of land between three notable depressions, the basins of Lake Michigan, Lake Superior, and the Mississippi. The summit of the swell lies within 30 miles of Lake Superior, whence there is a rapid descent northward, with gentler declines to the south-east and south-west, separated by a low swell extending from the summit southward into Illinois. This is traversed in the south-central portion of the State by a remarkable diagonal valley, occupied by Green Bay and the Fox and Wisconsin rivers, cutting it down to within about 200 feet of the lake levels. The easterly slope is traversed longitudinally by a ridge of Niagara limestone, running nearly parallel to the shore of Lake Michigan, at an average distance of about 30 miles.

The greatest topographical interest—and it is very considerable—lies in the minor surface features. The ice of the Glacial period invaded in force the eastern and northern parts of the State, while an area of 10,000 square miles in the south-western portion was left untouched. Flowing but very irregular contours, accented by morainic peaks and ridges, by gravel knolls, and by domes of drift, mark the former area; while deep dendritic valleys, erosion cliffs, and castellated outliers give more striking relief to the latter. About 2000 minor lakes dot the eastern and northern portions, all lying within the glaciated area, and caused by the irregular heaping of the drift, or by the erosion of the glaciers. Numerous waterfalls occur in this portion, likewise due to the disturbance of the river-courses by the ice incursion. None occur in the unglaciated area.