224 GEOLOGY OF EASTERN WISCONSIN. 



tremity to the region of Lake Winnebago, beyond which it declines. 

 On Lake Superior an analogous clay rises at least one or two hundred 

 feet higher. 



Aside from the general northward depression indicated by these 

 facts, a special flexure seems to have taken place in the region of Lake 

 "Winnebago, either of the nature of a greater depression during the 

 time of deposit, or of a greater elevation subsequently. This fact is 

 entirely in harmony with the concurrent indications of several pecu- 

 liar features in the underlying formations and general structure of the 

 region. It is on the basis of this general northward depression, and 

 on the sequence of the formations, that this and the associated de- 

 posits are referred to the Champlain period. 



III. BEACH FORMATION B. 



Reposing upon the Lower Red Clay, there lies a deposit of sand 

 and gravel, with included layers of .clay, reaching a thickness of 60 

 feet or more, and constituting a well defined formation. It differs in 

 no essential respect, so far as its character is concerned, from Beach 

 Formation A, which has already been described, and hence it will not 

 receive special description here. At some points however, where the 

 depositing waters found a rocky shore, instead of the accumulations of 

 clay, sand and gravel, large blocks of the neighboring limestone, more 

 or less eaten by the waters, are strewn on the shore in a manner sim- 

 ilar to that which is now being enacted on the rocky beach of the 

 Green Bay peninsula further north. The formation best exhibits itself 

 along the lake shore from Manitowoc northward, where fine vertical, 

 sections may be seen, one of which is illustrated in the accompanying 



figure. 



FIG. 13. 



PROFILE SECTION ON LAKE SHORE, NEAR MANITOWOC. 

 1. Lower Red Clay. 2. Sand Deposit. 3. Alternating Belts of Sand and Clay. 



It becomes a surface formation between the Upper and Lower Red 

 Clays. Appearing upon the lake shore in the vicinity of Manitowoc, 

 its surface exposure stretches northward in the valley of the East 

 Twin river into Kewaunee county, whence it curves slightly to the 

 eastward into the basin of the Ahnapee river, from the valley of which 

 it passes over the watershed into the Green Bay valley, which it skirts 

 on the east as far south as Lake Winnebago, whence it returns on the 



