888 THE GEOLOGY OF MINNESOTA. 



[Kames wells. 



in section 5, Mansfield, the morainic accumulations are less prominent and 

 give place to smoother, undulating or moderately rolling till; except that 

 here the stream is bordered by well-marked kames, or hillocks and ridges 

 of water-deposited gravel and sand. One ridge, or kame, twenty to forty 

 feet high, extends nearly a mile along the east side of the creek, separat- 

 ing it all this distance from a slough, to which two gaps supply outlets. 

 Before these gaps were cut through, the slough was probably a lake. 

 These kames are in large part gravel, very full of pebbles up to three or 

 four inches in diameter, fully half of them being well water-worn. They 

 also contain rarely boulders up to two or three feet in diameter. These 

 rock-fragments, like those contained in the till of this region, are mostly 

 granite, syenite, schists, and limestone. Though these kames are lower 

 than the Bear lake prairie, they are believed to have been formed at a 

 higher level, in the ice-walled channels of the glacial streams which car- 

 ried forward their finer gravel, sand and silt to that plain. When the ice 

 had wholly melted, these ridges of coarse gravel fell upon the till, which 

 gradually descends northwestward from the moraine in a smoothly undu- 

 lating surface, with no noteworthy accumulations of modified drift beyond 

 these kames. 



The plate (No. 14) which illustrates the geology of this county is designed only to show the 

 features and distribution of the drift. In the areas represented as till-covered will be found 

 numerous patches of modified drift which were too small to be noted. Of these, two areas of 

 gravel and sand, which are more important than others, should be mentioned. One is along the 

 Shell Rock river, particularly along the east side of the river, and the other extends northward 

 from Geneva lake. Throughout the very rough portions of the morainic till there is also a fre- 

 quent occurrence of large knolls and of flat tracts of modified drift, the morainic accumulation 

 itself often consisting largely of this. 



Wells. In the survey of the county considerable attention was paid to the phenomena of 

 common wells with a view to leain the nature and thickness of the drift, and the following list 

 is the result of notes made. 



Good water is generally found throughout the county, in the drift, at depths less than 

 eighty feet; but some deep wells that occur within the Cretaceous belt, in the western part of 

 the county, are spoiled by the carburetted hydrogen. This must arise from carbonaceous shales 

 in the Cretaceous, and indicates the extent of that formation. 



The only well in the county that is known to have struck bed-rock is that of the Minneap- 

 olis and St. Louis railway at Albert Lea. It is near the station, on a flat which is about twenty 

 feet below the main streets of Albert Lea and twenty feet above Albert Lea lake. 



Deep well at Albert Lea. 



1 . Clay, said to be free from gravel 34 ft. 



2. Quicksand 4 ft. 



3. Clay 32 ft. 



4. "Dark gray limestone," thought to be the same as that at Northwood 32 ft. 



5. White sandrock, giving a little water, which rose to within twenty feet of 



