4i6 



JAMES WALTER GOLDTHWAIT 



can cut with ease. Consequently the present shore south of Algoma 

 commonly consists of high red-clay cliffs, which are rapidly retreating 

 under the attack of the waves, and have long since eaten away the 

 abandoned shore-lines of higher stages. When fragments are pre- 

 served, moreover, they commonly show that the lake at the Nipissing 

 plane (the next important one above the plane of the present lake) 

 cut back beyond the earlier shore-lines of Lake Algonquin and Lake 

 Chicago. The record south of Sturgeon Bay, then, -is relatively 



Q 



Fig. 4. — Terrace and bluff of Lake Algonquin near Sturgeon Bay, 40 feet above 

 Lake Michigan. 



incomplete, and fragments of the lower stages are more common than 

 those of the higher. 



The same is true of the southeastern border of Green Bay. Along 

 the low western shore of Green Bay, on the other hand, deposition of 

 beach ridges has been the rule from the first, so that no cliff recession 

 at the lower stages has here destroyed the record of earlier stages. 

 There is an almost complete series of sandy ridges. But the weak- 

 ness of expression of these beaches, probably in large measure an 

 original weakness, together with the sandy structure which has per- 



