YELLOW MEDICINE, LYON AND LINCOLN COUNTIES. (JQ7 



Boulders. Wells.] 



as of shale, which could be certainly referred to the Cretaceous, were seen; and no quartzyte nor 

 . conglomerate. Many of the limestone fragments are obscurely fossiliferous. The top of this cut 

 is about 30 feet above lake Yankton, and perhaps five feet below the top of the mound in 

 which it is made. Similar gravel forms the subsoil, and extends to a depth of 30 feet in wells at 

 Balaton station, and reaches thence a half mile to the northwest beside the lake, and two or three 

 miles easterly along the railroad. 



Terrace-like outlines, noticed at a few places, as near the mouth of Stony run, upon the bluffs 

 bordering the Minnesota river in Yellow Medicine county, appear to have been wrought in the till 

 of the general drift-sheet during the excavation of this great valley. A terrace of modified drift 

 on the opposite side of the river in Chippewa county , indicates that this part of the valley has 

 been filled with gravel and sand to a depth of 30 or 40 feet above the present river. 



Boulders. Very abundant boulders occur upon the bluff of the Minnesota river along an 

 extent of two miles between one and three miles southeast from the mouth of the Yellow Medicine 

 river, in sections 34, 3, 2, 11 and 12, Sioux Agency. Tlie bluff here is knolly and in many places 

 thickly covered with large and small rock-fragments from the bottom to a hight 100 to 125 feet 

 above the river; but the till which forms the upper 50 feet of the bluff and the prairie at its top, 

 has only the usual small proportion of boulders. This feature was not noticed elsewhere upon the 

 bluffs in Yellow Medicine county, but is remarkably displayed in many places through the next 

 fifty miles in ascending the Minnesota river. It appears to be due to the occurrence in the drift- 

 sheet of a stratum of till thickly filled with boulders; and its origin is probably from a terminal 

 moraine accumulated in the early part of the ice age, and afterward covered by the more 

 extended ice-sheet of the later epoch, by which its mounds and hills of coarsely rocky drift were 

 spread in a nearly level layer and buried under an additional thickness of ordinary drift contain- 

 ing few boulders. Some portions of the ledgy bottomland two to five miles up the valley from 

 Granite Falls are very plentifully strown with boulders, which were probably derived from this 

 layer of the drift-sheet. They are especially noticeable in section 24, Stony Run, where, along 

 an extent of about a quarter of a mile, rock-fragments of all sizes up to six or eight feet in 

 diameter form almost the greater part of numerous drift-ridges that extend twenty to forty rods 

 from northwest to southeast, and rise some 20 feet above the general level of the valley. 



Wells in Yellow Medicine county. 



Examples of sections of the drift found by common wells in Yellow Medicine county are as 

 follows: 



Echo. Frederick Mecklanbuvg; sec. 8: well, 52 feet, bored two feet in diameter; soil, 2; 

 yellow till, 17; blue till, much harder, "like stone," 33; sand, 8 inches, with blue till below; water 

 rose eighteen feet in a half hour. 



Otis. R. W. Crandle;. sec. 31: well, 52 feet; soil, 2; yellow till, 15; very hard, dark blue till, 

 35; this well was given up as a failure at the depth of 50 feet; but Mr. Crandle decided to bore 

 down the length of a carpenter's auger, when, at two feet lower, water was struck and spouted up 

 six feet, rising in a short time thirty feet. This is on the high prairie, about 150 feet above the 

 Minnesota river. 



Granite Falls. C. P. Griswold; well, 55 feet; soil, 2; very coarse gravel, containing rounded 

 stones up to a foot in diameter, becoming below less coarse, and gradually changing to ordinary 

 gravel, 10 feet, containing a small supply of water in its lower part; hard yellow till, 5 feet; tena- 

 cious, sticky, hard, dark bluish till, 38 feet; some gray streaks were found in this lower till, but 

 no sandy layers and no water. 



Wood Lake. B. G. Hall; sec. 23: well 26 feet: soil, 2; sandy till, easy to dig, 6; yellow till, 

 picked, in the lower part mixed with bluish and ferruginous streaks, 14 feet, containing pulver- 

 ulent and soluble, white particles, in appearance like coarse sand; then, a bed of sand, 2 feet, 

 from which water slowly seeps, bitterish; underlain by blue till, much harder than the upper till, 

 2 feet and reaching lower. Another well, on lower land, fifteen rods distant, gets good water at 

 12 feet. Through all this region the blue till extends to a great depth, and is much harder than 

 the overlying yellow till. The wells of this township are mostly in till, and vary from 10 to 40 

 feet in depth, the shallow wells having generally the best water. 



John Besmern; sec. 26: well, 16 feet; all caving gravel and sand; situated on the southeast 

 slope of a kame-like knoll, fifteen feet above the general level. The top of this knoll, partly ex- 



