346 PLEISTOCENE OF INDIANA AND MICHIGAN. 



that the real ice sheets were relatively local and restricted bodies, spreading from centers of 

 growth in Labrador, Keewatin, Patricia, British Columbia, and Scandinavia. 



In thinking of this problem it is necessary to remember that most of the ice Woodward 

 reckoned upon was far away — half of it being distant over 90° of longitude and more than 38° 

 of latitude — and had therefore a relatively small effect on the total result. It was the ice that 

 stood near the lake that had the greatest effect and constituted the chief factor of deformation. 

 It is not surprising, therefore, that such small values have been found for its attraction. 



The features of this district bearing on the attraction of the ice sheet and its effect in de- 

 forming the lake surface are suggestive and in a general way appear to be confirmatory, but 

 they fail in some important respects to accord with expectation based on what is believed to 

 be sound theory. 



DEFORMATION EAST OF DEFIANCE MORAINE. 



As noted above, the limits of Lake Maumee in the region east of the Defiance moraine 

 appear to correspond in altitude with the middle beach of Lake Maumee west of that moraine. 

 It was formerly supposed that this beach extended about to Ashtabula, Ohio, without measur- 

 able tilting or deformation. But since the making of the topographic maps it is found that 

 beginning about at Cleveland this beach makes a relatively rapid rise to the vicinity of Mentor 

 and Painesville. The distance is 25 to 28 miles and the rise about 10 feet, an amount which 

 seems to accord fairly well with deformation found between Pandora and Findlay. 



The situation is much the same as that in the district just discussed, except that the con- 

 temporary position of the ice front is not accurately known. At the time of this beach the 

 margin of the ice lobe in Lake Erie probably ran nearly parallel with the south shore and not a 

 great distance from it. 



DEFORMATION IN FORT WAYNE DISTRICT. 



In discussing the first Maumee beach Mr. Leverett ' states that near the vicinity of the Fort 

 Wayne outlet this beach stood at 775 to 780 feet. Near the Ohio-Michigan State line several 

 observations unite in giving the beach an altitude about 26 feet higher — at West Unity, Ohio, 

 801 feet, at Fayette 798 feet, and at Fairfield, Mich., 799 feet, these points all being close in 

 front or west of the Defiance moraine. Northeast from Fairfield, on the inner or east side 

 of the Defiance moraine, the altitude of this beach seems to be slightly lower. 



Although this district lies within the "area of horizontality " and is therefore important 

 in the investigation of this question, topographic mapping has not yet been extended into it 

 and it seems too soon to discuss it. Other localities in the area of horizontality are found on 

 the shores of Lake Michigan southward from Grand Haven, but accurate surveys of them have 

 not been made. 



Several other localities seem at first to afford promising places for studying the effects of 

 ice attraction. One is the highest Maumee beach between Birmingham and Almont or Imlay, 

 Mich.; another is the Whittlesey beach from Richmond to Applegate or Carsonville, Mich.; 

 another is the Whittlesey beach between Dunkirk and Alden, N. Y., and still others are in 

 Ontario. But aU of these are in the region of stronger uplift from other causes and it would 

 seem hardly profitable to attempt to unravel their complex phenomena. 



ATTRACTION AT MODERATE DISTANCES FROM THE ICE. 



Variations of altitude other than those described above (p. 344) for the Maumee beach are 

 noticeable. Between Leipsic and Berea, Ohio, a distance of 115 miles, the middle beach rises 

 about 10 feet, or about 0.08 foot to the mile. Variations like this, amounting to 10 or 20 

 feet in 100 miles or more, probably occur in other places. It seems quite probable that such 

 a rise occurs between the head of the outlet near Fort Wayne and Findlay in connection with 

 the highest beach. Mr. Leverett found the hooked spit on the east side of the Sixmile Channel 

 at New Haven, Ind., to have an altitude of 786 feet, its crest being 2 or 3 feet higher than the 



i Mon. U. S. Geol. Survey, vol. 41, 1902, pp. 724-725. 



