420 



JAMES WALTER GOLDTHWAIT 



ridge at the 25-foot level at those places where no cliff recession has 

 occurred at a lower stage — viz., at Kencsha and in the Chicago dis- 

 trict — agrees with this view. The abundance of shells in the "Toles- 

 ton" beach, noted by Dr. Marcy before 1867,' and confirmed by 

 other collectors since that time (including a recent discovery by the 

 present writer in Evanston, 111.), when contrasted with the absence 

 of life in the 40- and 60-foot beaches, favors the idea that the Toleston 

 or 25-foot beach marks a lake of less frigid water than the glacial Lake 



Fig. 6. — Terrace and bluff of the Nipissing shore-line north of Algoma, Wis. In 

 the foreground the old shore-hne is cut away by the receding cliffs of the present lake. 

 In the distance the Nipissing terrace is covered with a veneer of wind-drifted sand. 



Chicago. Similar shells have been found in the Algonquin beaches 

 on the west side of Lake Huron, by those working in Michigan. But 

 of still greater significance is the fact that Mr. F. B. Taylor, Dr. A. C. 

 Lane, and others in Michigan have found the Algonquin beach in a 

 horizontal position in the southern part of the Lake Huron basin, 25 

 feet above the lake.^ If there has been no tilting in the Huron basin 



1 See Geological Survey of Illinois, Part III, "Geology and Paleontology," p. 250 

 (1868). 



2 See Geological Survey of Michigan, Report on Huron County, by A. C. Lane, 

 Vol. VII, Part II, p. 75. 



