Wisconsin Kettle Moraine. 207 



to furnish fine opportunities for decisive investigation. Of the 

 many details collected, there is room here for a single illustrative 

 case only. The Green Bay loop of the range surrounds on all 

 sides, save the north, several scattered knobs of quartzite, por- 

 phyry and granite, that protrude through the prevailing lime- 

 stones and sandstones of the region. These make their several 

 contributions to the material of the range, hut only to a limited 

 section of it, and that invariably in the direction of glacial striation. 

 Any given segment of the range shows a notable proportion of 

 material derived from the formation adjacent to it, in the direc- 

 tion of striation; and a less proportion, generally speaking, from 

 the succeeding formations that lie beyond it, backward along the 

 line of glacial movement for three hundred miles or more. It is 

 undeniable, that the agency, tuhich produced the range, gathered its 

 material all along its course for at le ist three hundred miles to the 

 northioard, and its largest accumulations were in the immediate 

 vicinity of the deposit. For this reason, as the range is traced along 

 its course, its material is found to change, both lithologically and 

 physically, corresponding to the formation from which it was 

 derived. 



These facts find ample parallel in the moraines of Switzerland. 

 The marginal portion of the great moraine of the ancient expanded 

 glaciers, on the flanks of the Juras, is composed, very largely, of 

 boulder clay, derived from the limestones that lie in its vicinity, 

 while the quantify of material derived from the more distant for- 

 mations of the Alps is quite subordinate. Of the more recently 

 formed moraines, those derived from the Bois, Yiesch, Ehone, 

 Aar, and other glaciers, which pass over granitic rocks, consist 

 quite largely of sand, gravel, and boulders, clay being subordinate, 

 while those glaciers of the Zermatt region, that pass mainly over 

 schistose rocks, and the Grindelwald glaciers, that, in the lower 

 part of their course, traverse limestone, give rise to a decided 

 amount of clay. The moraines, previously referred to as minia- 

 ture kettle ridges, are composed of commingled unstratified debris, 

 in the main, but there are instances of assorted and stratified 

 material. The inner moraine of the upper Grindelwald gl icier 

 presents much fine assorted gravel and coarse sand, heaped up, 



