Mat 8, 1908] 



SCIENCE 



725 



cured, under the direction of P. B. Taylor, 

 on the east side of Lake Michigan, from 

 the Straits of Mackinac southward and on 

 the Upper Peninsula southward to Hol- 

 land, Mich. From these data several dis- 

 tinct water planes of the extinct lakes, 

 Algonquin and Nipissing, were recognized. 

 They were shown in detail on a plotted 

 profile. The inclined planes converge 

 southward, and appear to coincide near 

 Onekama, Mich., and Green Bay, Wis., to 

 form a single horizontal water plane at the 

 height of 596 feet A. T. or 15 feet above 

 Lake Michigan. 



The correspondence of this series of 

 raised beaches with those studied and de- 

 scribed by J. W. Spencer east of Lake 

 Huron and Georgian Bay was discussed. 

 The extension of the profile northward to 

 the Sault Ste. Marie indicated a probable 

 correlation between the raised beaches bor- 

 dering Lake Michigan and those of the 

 Superior Basin. 



Earth Movements in the Laurentian Basin 

 Since its Occupation by the Ice: Will- 

 iam Herbert Hobbs, Ann Arbor, Mich. 

 The introduction of precise leveling to 

 determine the present positions and alti- 

 tudes of the abandoned shore lines within 

 the Laurentian Basin, as indicated in the 

 last paper, has opened a new era of study 

 of the earth movements which have taken 

 place within this province since the Pleis- 

 tocene glaciation. Professor Hobbs 's paper 

 was a discussion of problems the solution 

 of which was sought in field work under- 

 taken for the Michigan Geological Survey 

 during the season of 1907. 



A Review of the Great Lakes History, with 

 Special Reference to the Deformation of 

 the Ancient Water Planes: Prank B. 

 Taylor, Port Wayne, Ind. 

 South of the line passing through Lake 



St. Clair and Ashtabula, Ohio, the ancient 



beaches are substantially horizontal, and 

 they are the same around the southern 

 third of Lake Michigan, as shown by Pro- 

 fessor Goldthwait. North of this, in the 

 Lake Michigan Basin, the beaches above 

 the Algonquin beach are all tilted upward 

 towards the north; in the Lake Huron 

 Basin they are tilted upwards towards the 

 north-northeast, the rate being a foot to 

 the mile or less. 



The Algonquin beach keeps horizontal 

 for about 100 miles farther north than the 

 others in both basins. Then it begins to 

 rise towards the north; for the first fifty 

 miles at a rate of nearly one foot per mile ; 

 then for about thirty miles at a rate of a 

 little more than two feet per mile ; and then 

 for at least fifty miles and perhaps farther 

 at a rate of more than three and a half 

 feet per mile. The rate of uplift east of 

 Lake Huron seems slightly greater than in 

 the Lakes Michigan and Superior basins. 

 The direction of maximum rise is about 

 north-northeast east of Lake Huron and 

 nearly north in the Lake Michigan Basin. 



The Kirkfield outlet of the Algonquin 

 to the Trent Valley in Ontario was dis- 

 cussed and it was shown that the opening 

 of this outlet lowered the level of Lake 

 Algonquin at least 40 or 50 feet, and that 

 at this time the ice sheet had withdrawn 

 from all of the Lake Michigan Basin, from 

 nearly all of the Lake Huron Basin, and 

 probably from much of the Lake Superior 

 Basin. Lake Algonquin was at first con- 

 fined to the Lake Huron Basin with its 

 outlet at Port Huron. Whether its merg- 

 ence with Lake Chicago occurred before or 

 after the opening of the Kirkfield outlet is 

 not known. The Kirkfield outlet was in the 

 area of great uplift and was soon carried 

 up to a higher altitude than the old outlet 

 at Port Huron, to which place the discharge 

 was then returned. The uplift then con- 

 tinued, at first slowly, but later with rela- 



