236 J. AV. GOLDTHWAIT ALGONQUIN AND IROQUOIS BEACHES 



table. Plate 5, although a small-scale map, does not exaggerate the 

 uniformit}^ 



THE HORIZONTAL PORTION OF THE ALGONQUIN PLANE 



Around the southern half of Lake Michigan, and near the south ends 

 of Saginaw Bay and Lake Huron, the Algonquin beach is almost, if not 

 quite, horizontal. The identity of the beach is somewhat obscured by 

 the presence of another strong shoreline, the Nipissing, which stands 

 only about 12 feet below the Algonquin in both basins and which replaces 

 it for long distances where cliff recession has been rapid and long con- 

 tinued. ^° Moreover, cliff recession along the modern lake front has de- 

 stroyed considerable stretches of both of these ancient strands. Never- 

 theless, the data collected seem complete enough to show that the Algon- 

 quin beach is virtually horizontal over this wide area. 



The following table gives the altitudes of the Algonquin beach or its 

 supposed equivalent at 19 localities in or near the region of horizontality. 

 All the measurements except the one at Port Sanilac were made with the 

 wye-level : 



Altitudes of the Algonquin Beach in the Region of Horizontality. 



LocaUtv. 



Two Rivers, Wisconsin, 



Evanston, Illinois. 



Rogers Park, Illinois 

 Holland, Michigan. . 



Spring Lake, Michigan . . 



Muskegon, Michigan 



Arcadia, Micliigan 



Herring Lake, Michigan. 

 P>ankfort, Michigan. . . . . 

 AVortli, Michigan 



Alti- 

 tude. 



Feet. 



607 



605 



604 

 604 



603 



604 



603 



607 



605 



607 



Authoritv. 



G old th wait. 



Goldthwait. 



Goldthwait. 

 Taylor and 



Goldthwait. 

 Taylor and 



Goldthwait. 

 Taylor and 



Goldthwait. 

 Taylor and 



Goldthwait. 

 Taylor and 



Goldthwait. 

 Taylor and 



Goldthwait. 

 Taylor and 



Goldthwait. 



Reference. 



Bulletin Wisconsin Geological 

 and Natural History Survey, 

 No. 17, 1906, page 60, figure 

 11, and plate 12, 



Bulletin Illinois Geological Sur- 

 vey, No. 7, 1908, pages 64-65. 



Idem, page 66. 



II. S. Geological Survey, 



V. S. Geological Survey, 

 U. S. Geological Survey. 

 U. S. Geological Survey. 

 U. S. Geological Survey. 

 U. S. Geological Survey. 

 U. S. Geological Survey. 



10 See Abandoned shorelines of eastern Wisconsin. Bulletin of the Wisconsin Geo- 

 logical and Natural History Survey, no. 17, 1906, pp. 44-45 ; and Reconstruction of 

 water-planes of the extinct glacial lakes in the Lake Michigan basin. .Tournal of 

 Geology, vol. 16, 1908, pp. 459-476. In the latter the altitude of the Algonquin beach 

 was placed provisionally at 596 feet instead of 607 feet. The statement was made, 

 ho ever, that this 596-foot beach might prove to be the Nipissing, and that the Algon- 

 quin might be expected at 607 feet (see p. 472), 



