GLACIAL DAMS, LAKES, AND WATERFALLS. 361 



All the lines of the kame-deposits in Maine, New Hamp- 

 shire, and Massachusetts are marked by the frequent occur- 

 rence of lakes and dry depressions of this description. 

 " Tight Pond," the name of one in the vicinity of Conway, 

 N. H., is suggestive of its character. The resemblance so 

 often noted by tourists between the scenery of Michigan 

 and that of large portions of Ireland is produced by the pre- 

 ponderance in both regions of this class of lakelets. The 

 innumerable lakes of Wisconsin and Minnesota had a similar 

 origin, and are limited chiefly to the tortuous line of the 

 great Kettle Moraine, heretofore described as being so 

 marked a feature in the topography of the country between 

 Lake Michigan and Dakota. 



It was a long time before the true origin of these lake- 

 lets in the Northwest was suspected. But no sooner was 

 Mr. Upham set to survey the field in Minnesota, than, with 

 his knowledge of the glacial phenomena of New England, 

 he detected their character, and at once adopted a provisional 

 hypothesis by which he successfully and economically direct- 

 ed his future glacial investigations in the State. The lake- 

 lets and dry depressions above Minneapolis, including even 

 Lake Minnetonka itself, he perceived to be kettle-holes, such 

 as characterize the terminal moraine on the southern shore 

 of New England, and at once inferred that the moraine in 

 that State would be found running along the curved lines 

 formed by these lakelets, as laid down upon the maps by the 

 topographical surveyors. There was a belt of such lakelets 

 running a little west of north from Minneapolis, between 

 the valley of the upper Mississippi and that occupied by the 

 Minnesota and the southern part of the Red River of the 

 North. In the vicinity of Minneapolis there was also a 

 peculiar enlargement of this area of lakelets, whence it ex- 

 tended into northern Iowa, but, for a width of sixty or 

 seventy miles, and a length of two hundred and fifty or 

 three hundred miles up and down the Minnesota Yalley, 

 there was a striking absence of lakes upon the maps. They 

 reappeared again, however, to the west, in a line nearly par- 



