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S. WEI DM AN 



the narrow valley of the Wisconsin to the flat-topped uplands, 

 ridges, and valleys beyond, he would see that the uplands rise 

 approximately to his own elevation and form an even crest-line 

 along the horizon. If he should look northward, the even sky- 

 line would be seen to rise gently but persistently to the northeast. 

 Looking to the west, the even crests of the hills are seen to 

 return to an elevation equal to his own. However, if he should 

 turn to the south, Rib hill and the adjoining Mosinee hills, six 



Fig. I. — View looking east across the Wisconsin valley to the even-summited 

 upland of the dissected peneplain. At Wausau. 



miles southwest of Wausau, would rise before him and obstruct 

 his view of the even sky-line which swings away beyond and 

 falls not only far below the summit of Rib hill, but also much 

 below his own position. The even-summit surface of the main 

 upland area is the most striking feature of the landscape and at 

 once suggests an ancient plain sloping upward to the north, 

 below which the Wisconsin river and its tributaries have sculp- 

 tured their valleys, and above which project a few isolated pointed 

 ridges and hills like Rib hill and the Mosinee hills. 



Rock structure of the pre-Cambrimi. — If the observer should 

 now descend the upland and note the character of the rocks 

 exposed along the valley sides and on the flat-topped uplands 



