THE GLACIAL DRIFT. 63], 



truth of this proposition, of which, liowever, a complete demonstra- 

 tion appears to be at hand. In all the country just inside of the 

 Kettle Range, we find that glacial stri83, lines of glacial erosion, and 

 lines of travel of erratics, all preserve a position at right angles to the 

 course of the range, although that course veers in the southern part 

 of the district from west to north. East of the Central Wisconsin 

 district, as previously stated, the Kettle Kange extends eastward and 

 northeastward to the dividing ridge between the valley of Lake Mich- 

 igan and the valley in which lie Green Bay, Lake Winnebago and the 

 head waters of Eock river, and along this ridge northward into 

 Green Bay peninsula. All along this part of its course. Prof. 

 Chamberlin has found the glacial striaj pointing east of south, and 

 towards the Kettle Range, whilst along the middle of the Green Bay 

 valley, he finds the striae directions parallel to the main axis of the 

 valley, or a little west of south. On the west side of this great valley, 

 and along the eastern border of the Central Wisconsin district, the 

 striae trend about southwest, whilst still further west they gradually 

 trend further to the west, becoming at last nearly due west, or at 

 right angles to the western Kettle Range. 



We have then a most beautiful proof that at one time the Green 

 Bay valley was occupied by a glacier, which was not merely part of a 

 universal ice sheet, but a distinctly separate tongue from the great 

 northern mass. The end of this glacier was long in noi-thern Rock 

 county, its eastern foot on the east Wisconsin divide, and its western 

 on the summit of the divide between the Fox and Wisconsin river 

 systems, as far south as southern Adams county, after which it crossed 

 into the valley of the Wisconsin, and from that into the headwaters 

 of the Catfish branch of Rock river, in the Dane county region. 

 Whilst the main movement of the glacier coincides in direction with 

 the valley which it followed, it spread out on both sides in fan-shape, 

 creating immense lateral moraines. Peculiar circumstances caused 

 the restriction of the eastern moraine to a narrow area, whilst that on 

 the west, having no such restriction, spi-ead out over a considerable 

 width of country, the breadth of the moraine reaching in Waushara 

 county as much as 25 miles. Of course this width of moraine must 

 have been due to the alternate advance and retreat of the glacier foot. 

 Such an advance and retreat appears moreover to be recorded in the 

 long lines of narrow sinuous ridges, each marking perhaps the posi- 

 tion of the glacier foot, or a portion of it, during a certain length of 

 time. The intersecting of these winding ridges, which have no par- 

 allelism at all with one another, appears to me to have been the main 

 cause of the formation of the kettle depressions. Col. Whittlesey ^ 

 ' Smitlisonian Contributions to Knowledge. 



