228 GEOLOGY OF EASTERN WISCONSIN. 



of sufficient space for the wide discussion of the Champlain deposits 

 of the great lake region, to which a proper treatment of the subject 

 would lead, it is deemed best to leave the question for future consid- 

 eration. 



The elevation of the oeach ridge which marks the western limit of 

 these deposits above Lake Michigan is as follows: 



Near the Illinois line 55 feet. 



A little farther north 53 " 



In Sec. 18, S. E. qr. T. 1, R. 23 E 40 " 



In Sec. 1, middle S. line S. E. qr. T. 2, R. 22 E 44 " 



In Sec. 19, S. E. corner T. 3, R. 23 E 80 " 



In Sec. 29, S. E. qr. S. line T. 4, R. 23 E 68 " 



TERRACES. 



Just north of the lighthouse north of Milwaukee, the bank facing 

 the lake is low, but a few rods back there is a well defined terrace 

 running nearly parallel to the lake shore, and rising from 50 to 100 

 feet above it. This continues northward, with interruptions, for sev- 

 eral miles. A similar terrace accompanies the greater portion of the 

 shore line between Port Washington and Sheboygan, and near Cen- 

 terville there is a feeble development of the same phenomenon, beyond 

 which it is absent for a considerable interval. Just north of Alma- 

 pee the terrace reappears in sharp and rigid outline, and extends with- 

 out essential interruption to the vicinity of Sturgeon Bay. It attains 

 in this portion a height of 75 feet. Between the terrace and the lake 

 a mature growth of forest vegetation, of a highly mixed character, is 

 to be found. 



Beach Ridge of Sand. In the vicinity of Sturgeon Bay, the ter- 

 race is replaced by a beach ridge of rather fine yellow sand. With lim- 

 ited interruptions this ridge extends to Port de Morts. 



Beach Ridge of Rock-fragments. As we round the point and re- 

 turn on the Green Bay side, much more frequent interruptions occur 

 from the rocky promontories that characterize this shore; and instead 

 of being sandy, the ridge is here chiefly formed of chip-stone with par- 

 tially rounded angles, and of the flat pebbles that mark a rocky beach, 

 where the fragments are worn rather by sliding than by rolling. 

 These form sharp ridges, sometimes rising 20 to 30 feet above their 

 bases, on either side, and become a very conspicuous feature at 

 Ephraim, Fish Creek, Egg Harbor, and elsewhere. 



Terraces of Rock. Along this shore also, notably between Egg 

 Harbor and the mouth of Sturgeon Bay, terraces of rock sustain a re- 

 lation to the present shore altogether similar to that held by the clay 



