156 THE GLACIAL LAKE AGASSIZ. 



measuring 20 by 30 feet and projecting 1 to 2 feet above the surface, and 

 shown by digging to be more than 3 feet thick. All these are grayish- 

 yellow, very compact magnesian limestone, similar to that which is found 

 forming bowlders of equal aljundance near Audubon and the White Earth 

 Agency in Becker County, Minn., and again on the massive morainic hills 

 near Fort Totten, on the south side of Devils Lake. In these localities 

 the limestone bowlders sometimes occur in equal or even greater numbers 

 than those of the Archean rocks; but generally throughout this region the 

 proportion of such limestone masses in the drift is very small, averaging 

 probably not more than a hundredth part of the large bowlders, though the 

 portions of the gravel of the drift supplied respectively by the limestone 

 and the Archean rocks are commonly about equal. They are like the out- 

 crops of magnesian limestone in the neighborhood of Winnipeg, in Mani- 

 toba, 165 to 180 miles distant to the north, which are its nearest natural 

 exposures. 



West of Butte Mashue. the Dovre moraine is represented by knolls 

 and hills 25 to 75 feet high, which continue to the prominently rolling 

 land surrounding Norway Lake, in the northeast corner of township 147, 

 range 60. Next this moraine extends northward in an inconspicuous belt 

 of knolly and rolling till to low hills in or near section 23, townshiji 149, 

 range 60 ; and thence, turning to the west-northwest, it holds this general 

 course through a distance of 30 miles to the Devils Heart Hill. It crosses 

 the Sheyenue River in the southeast part of township 150, range 61, and 

 forms a conspicuous belt of hills, 100 to 150 feet high, along the south side 

 of township 151, range 63, 4 to 5 miles south of Free Peoples Lake. A 

 lower but well-marked series of morainic hills and knolls, mostly 40 to 60 

 feet high, with very abundant bowlders, curves thence northwest and north, 

 passing through the center of township 151, range 64, to tlie Devils Heart. 

 Again, onl}' a few rods north of the base of that hill, a t}-pically in-egular 

 belt of very rocky morainic knolls, 30 to 50 feet high, occupying a width 

 of only 20 or 30 rods, ti-ends from east-southeast to west-northwest, and 

 forms the frontal line of the chief morainic tract bordering the south side 

 of Dexnls Lake (PI. XVIII). The Dovre moraine south of the Devils 

 Heart Hill would thus join a larger morainic tract on the north, which 



