460 THE GEOLOGY OF MINNESOTA. 



[Drift and contour. 



it may possibly represent either of the last. The nearest natural exposure 

 of any rock older than the drift is thirty miles distant to the southeast, 

 being on Lime creek in southwestern Worth county, Iowa. There the 

 Hamilton limestone of Devonian age is found, and extends thence south- 

 east to the Mississippi, having abundant outcrops along the Shell Rock and 

 Cedar rivers. 



Indications of the existence of Cretaceous beds containing lignite are reported to have been 

 found in the S. W. i of section 11, Verona. Mr. John Crapsey states that a great number of 

 pieces of lignite, up to eight inches in diameter, were obtained by him there from the drift or 

 talus forming the lower part of the east bluff of the Blue Earth river, a little above an island; and 

 that near by the bed of the river seems to be a ferruginous sandstone or conglomerate. It is inter- 

 esting to compare this with Prof. Bechdolt's observation (page 435) that fragments of lignite occur 

 frequently in the alluvium of this river at its mouth. The layers of Cretaceous lignite in Minne- 

 sota, however, are too thin to be of value as a source of fuel; though they lu.ve supplied fragments 

 found sparingly in the drift throughout the western two-thirds of the state. 



Drift and contour. 



The thickness of the drift upon this county probably varies from 75 to 

 200 feet, averaging 125 or perhaps 150 feet. It is composed mainly of till, 

 which encloses occasional veins and beds of gravel and sand, and shows the 

 same differences in color, hardness, and other characters, that have been 

 mentioned more particularly in the report of Blue Earth county. 



In northeastern Faribault county, the east half of Foster has a moderately undulating surface, 

 composed of till, excepting occasional knolls or mounds of gravel and sand. From Freeborn lake 

 to Wells, and thence north, northwest and west, to the north line of the county, to Minnesota and 

 Lura lakes, and to Easton, the surface is very smooth and flat or more commonly somewhat undu- 

 ting till, the descent of five to fifteen feet from the highest portions to the shallow depressions of 

 sloughs being by long slopes. This area includes the west two-thirds of Freeborn and Carlston 

 in Freeborn county; and, in Faribault county, all of Dunbar and Minnesota Lake, Clark, except- 

 ing its southwest corner, the northeast part of Walnut Lake, and nearly all of Lura, except part 

 of its southwest quarter. 



Again, on the other side of the moraine which extends northwestward from Kiester, flat 

 or only slightly undulating till covers the southern and western parts of the county. Blue Earth 

 river and its East fork have their course nearly along the center of this tract, from the west side 

 of the Kiester hills westward to Blue Earth City, and then north by Winnebago City into Blue 

 Earth county. The townships in this area are Seely, Brush Creek, Rome, Emerald, the south- 

 western half of Barber, Elmore. except a width of one to one and a half miles on its south side, 

 Blue Earth City, Prescott, Delavan, Pilot Grove, except a width of one and a half miles on its 

 south side, Jo Daviess, Verona, and Winnebago City. 



Glacial lake in the basin of the Blue Earth river* The contour in these 

 townships, as also in the northeast part of this county, in southwestern 

 Waseca county, and through most of Blue Earth county, is generally quite 

 flat, the drift being spread with an unusually smooth and even surface, 

 nearly as in the Red river valley. The material of all these tracts is till, 



*First described in the ninth annual rep >rt, page 34V 



