BIG STONE AND LAC QUT PABLE COUNTIES. 627 



Buried moraine. Red till-] 



of Lac qui Parle, connected with the Minnesota valley and running approximately parallel with 

 it, reaching 40 to 80 feet below the general level of the drift-sheet, and varying from an eighth to 

 a half of a mile in width, frequently have their bed upon this stratum of boulders. On the bluff 

 of till which rises at the southwest side of the lower half of Lac qui Parle, this layer in some 

 places, as in sections 4, 5 and 9, of Lac qui Parle township, forms a rocky, very narrow terrace, at 

 a horizontal line about 75 feet above the lake and 25 feet below the top of the bluff and surface of 

 the adjoining country; and the more gradually sloping ascent from the northwest half of Lac qui 

 Parle shows many very rocky places 40 to 60 feet above the lake, which are probably also a part of 

 this buried moraine. A similar narrow terrace-mark, abundantly strown with boulders, is gen- 

 erally noticeable upon the bluffs at each side of the Minnesota river, at a bight of 50 to 60 feet 

 above it and some 50 feet below the general level, all the way from Lac qui Parle to Montevideo. 

 Further exposures of this rocky stratum in the till are seen in the Minnesota valley below Lac 

 qui Parle county, at many places, to a point three miles below the mouth of the Yellow Medi- 

 cine river. 



Northwesterly from the remarkable Correll plain, boulders are occasionally seen in great 

 abundance within the valley or on the bluffs that enclose the Minnesota river and Big Stone and 

 Traverse lakes. About two and a half miles east of Odessa station, a boulder of exceptional size, 

 being fully twenty feet in diameter, lies at the north side of the railroad. Within a mile farther 

 west are several very rocky knolls and short ridges, extending five or ten rods, trending approxi- 

 mately from west to east, and rising 15 to 30 feet above this part of the bottomland, which is not 

 reached by the highest floods of the Minnesota river. 



Two other localities also deserve mention, as exhibiting very plentiful boulders, the origin 

 of which is difficult to suggest, unless they are outcropping portions of this buried moraine. One 

 is at the southeast corner of section 15, in the west part of Prior, where a ravine, about six 

 rods wide and twenty feet deep, has the upper part of the slope on each side very profusely 

 sprinkled with granite boulders up to three or four feet in diameter, while only a few boulders are 

 seen on the surface of the region adjoining or along the bottom of the ravine. The same feature 

 is also noticeable in a less degree upon other ravines northeast of Big Stone lake, while in the 

 same region are seen occasional knolls or swells, 5 to 15 feet high, abundantly covered with large 

 and small rock-fragments. 



The second locality where boulders are specially remarkable is at a cut on the Hastings 

 & Dakota railroad about five miles west of Big Stone City. This cut is 5 to 10 feet deep and an 

 eighth of a mile or more in length, and is approximately at the average hight of the surface of 

 the drift-sheet in its vicinity. Boulders here are exceedingly abundant of all sizes up to ten 

 feet in diameter, but are confined to the surface and the upper two or three feet, and are com- 

 paratively rare below, being not more plentiful than is usual in the till throughout Minnesota. 

 Next west of this cut is a valley 15 to 20 feet lower and nearly an eighth of a mile wide, almost 

 destitute of boulders though apparently till, while the land at its west side again exhibits a sur- 

 face over which they are thickly strown. 



Red till. Besides the upper yellowish till (changed to this color by 

 weathering) and the lower dark bluish till, which ordinarily make up the 

 whole thickness of the glacial drift in this region, it exhibits at a few pla- 

 ces, below the foregoing, a distinctly reddish till, quite different in color 

 from the other two, and like the red till which overspreads northeastern 

 Minnesota from lake Superior to Saint Paul and Minneapolis. In that part 

 of the state the direction of glacial motion was southwesterly, and the red 

 color of the drift appears to be due to the large proportion of its material 

 which was gathered from areas of red sandstone and shales in the region of 

 lake Superior. Upon the western two-thirds of Minnesota the ice-currents 



