THE GLACIAL DRIFT. 615 



Drift hills and ridges occur over all of the drift-bearing area of 

 Central AVisconsin. In the region north of the east and west drift 

 limit, in Marathon, Wood, and Clark counties, they do not, however, 

 show any distinct morainic character; but in Dane, Sank, Columbia, 

 eastern Adams, Marquette, Grreen Lake, AVaushara, Waupaca and 

 Portage counties, they show this character in a marked degree. More- 

 over, there is, in these counties, a certain belt of country, the western 

 border of which is never very far from the eastern edge of the drift- 

 less area, in which the " knobby " drift hills reach an unusual de- 

 velopment, the drift materials are thicker than elsewhere, and the 

 surface of the country is dotted with circular or winding depressions, 

 without outlet, of very varying size, and often occupied by ponds or 

 lakes. To these depressions, in certain other parts of Wisconsin, 

 where they are to be recognized on a still larger scale, the name of 

 " potash kettles" has been applied, in allusion to their common shape; 

 and the belt of country in which they occur has been designated as 

 the " Potash Kettle Range," or, more simply, the "Kettle Range." 

 These latter names have heretofore been applied especially to a 

 narrow and very marked range which follows the divide between 

 the valley of Lake Michigan and that in which lie Green Bay, 

 Lake Winnebago, and the head waters of Rock river. Prof. 

 Chamberlin has traced this belt southward to the northeastern part of 

 Rock county, where he .finds it bifurcating, one branch running south- 

 eastward into Illinois, whilst the other, curving west and northwest, 

 enters the Central Wisconsin district on the south line of Dane 

 county, in the towns of Rutland and Dunkirk. 



From the south line of Dane county northward, the " Kettle Range" 

 is now recognized for the first time, having been traced for a distance 

 of over 120 miles, as far as the line of the Wisconsin Central Rail- 

 road, in Portage and Waupaca counties; beyond which it is known 

 to extend until it becomes merged into the great accumulations of 

 morainic drift which stretch from the head waters of the Wolf and 

 Oconto rivers westward, over a large part of the Archaean region of 

 the north part of the state. The Central Wisconsin " Kettle Range " 

 reaches in parts a much greater width than that of the eastern part of 

 the state, and its inner edge is not so well defined. These differences, 

 however, admit of a satisfactory explanation. Plate XXYI shows 

 the position of the Central Wisconsin Range, whose course and char- 

 acter are described in more detail in what follows. 



Beginning on the south, we find, in the towns of Rutland, T. 5, R. 

 10 E., western Dunkirk, T. 5, R. 11 E., and northeastern Oregon, 

 T. 5, R. 9 E., a considerable development of knolls and ridges of 



