CORRELATION OF RAISED BEACHES 423 



CONCLUSIONS 



A detailed investigation of the terraces and raised beaches in 

 eastern Wisconsin, with many measurements by spirit level, leads to 

 the follovv^ing conclusions. 



1. There is a series of warped water- planes of Lake Algonquin, 

 which rise at a moderate rate north of Sturgeon Bay, diverging, fan- 

 fashion, until the highest is 90-95 feet above Lake Michigan at Wash- 

 ington Island. The divergence of these planes is interpreted to mean 

 earth-movements contemporaneous with the Lake Algonquin stages. 

 The tiltings seem to have decreased greatly in measure south cf Stur- 

 geon Bay, dying out in the vicinity of Two Rivers, where the Algon- 

 quin beach stands about 26 feet above the lake. South of that point 

 the Algonquin shore-hne is thought to be horizontal above Lake 

 Michigan and represented by the highest beach of the "Toleston" 

 group in the Chicago district, at a height of 20-25 ^^^t, just as in 

 the southern part of Lake Huron basin the Algonquin seems to be 

 horizontal at a 25-foot level. 



2. A shore-line of remarkable strength, usually marked by high- 

 cut bluffs and terraces, which lies everywhere below the Algonciuin sand 

 in a horizontal position along the whole Wisconsin shore, is regarded 

 as the Nipissing shore-line. At Washington Island this terrace is 

 20-22 feet above the lake; but it gradually declines to 18-20 feet at 

 Sturgeon Bay and 16-18 feet at Two Rivers, reaching 14 feet at Cen- 

 terville, at which level it seems to become horizontal and to be repre- 

 sented by strong 14-foot terraces in Sheboygan county, near the 

 Illinois state line, and in the Chicago district. 



3. The Glenwood or 60-foot and the Calumet or 40-foot beaches 

 of Lake Chicago are poorly preserved north of Racine, but seem to 

 run to Sheboygan, possibly being obliterated north of Manitowcc by 

 an advance of the ice which formed the Manistee (Mich.) mcraine. 



4. If this identification and correlation is correct, one of the out- 

 lets for Lake Algonquin was the Chicago cutlet, the sill cf which 

 is 8 feet above Lake Michigan. The depth cf water in the Chicago 

 outlet would have been slight after the earliest stages of Lake Algcn- 

 quin, however; so the outlet at Port Huron probably played a more 

 important part. 



