FREEBORN COUNTY. 



Modified drift | 



Iowa. This is a flat plain, consisting, beneath its fertile soil, of stratified 

 sand and gravel. It is bounded on the east and southeast by Bear lake and 

 Lime creek. Rolling areas of till jut up, island-like, twenty to forty feet 

 above this plain in the three miles next southwest from Bear lake. The 

 highest part of this expanse is its northwest and west border, which rests, 

 along most of its extent, on the flanks of morainic hills. From this side a 

 scarcely perceptible slope descends eastward thirty or forty feet in a dis- 

 tance varying from three to six miles, and terminates by descending beneath 

 the water-level of Bear lake, which this modified drift bounds with a very 

 low and flat, marshy shore. It is evident that the waters from ivhich this 

 plain of sand and gravel was deposited flowed in the direction of its slope, 

 from west to east; and it is demonstrable that they were poured down upon 

 this area, loaded with detritus, from the melting surface of ice that covered 

 the country adjacent westward. 



Bear lake prairie is surrounded by knolly and hilly accumulations of 

 till, with an abundance of boulders and stones enclosed and strewn upon 

 its surface, belonging to the inner or western belt of the terminal moraine. 

 At the east these scattered and irregularly grouped hills rise twenty-five to 

 fifty feet above Bear lake and Lime creek. At the west, in sections 31 and 

 32, Mansfield, they rise fifty to one hundred feet above this plain of modi- 

 fied drift; and three to five miles farther northwest in Kiester, Faribault 

 county, they attain a hight fully 150 feet above the upper west edge of this 

 plain, or about 200 feet above Bear lake. From the "Kiester hills a series of 

 morainic accumulations extends twenty-five miles or more northwestward, 

 crossing Faribault county. At two places on the west border of Bear lake 

 prairie, head-streams of the East fork of the Blue Earth river have their 

 sources and thence descend westward and northward. One of these is 

 Brush creek, which begins upon an area of low, moderately undulating till 

 in sections 29 and 30, Mansfield, and flows south of the Kiester hills. The 

 other is Jones' or Dunnell's creek, which rises in springs in the north- 

 east quarter of section 17, Mansfield, issuing at the base of a bluff or bank 

 of gravel and sand about twenty-five feet in hight, from whose top the 

 broad Bear lake prairie stretches eastward. For a considerable distance 

 thence northward, in section 8. this stream flows in a ravine forty to sixty 

 feet deep, enclosed by rough knolls of morainic till. Along its next mile. 



