624 THE GEOLOGY OF MINNESOTA. 



[Modified drift and alluvium. 



at Ortonville one to one and a half feet, while an equal rise is occasioned by a similar northwest 

 wind. 



The Minnesota river along its first ten miles below Big Stone lake, at its ordinary stage of 

 water in summer, averages only one to two feet in depth. In its next fifty miles, before reaching 

 Granite Falls, it receives three large affluents, the Lac qui Parle, Pomme de Terre, and Chippewa 

 rivers; and its width is expanded to about a hundred and fifty feet, with volume sufficient to fur- 

 nish power for large flouring mills. During the high water of spring about twenty years ago, a 

 steamer, said to have been a hundred and twenty-five feet long, was run from Saint Paul up the 

 Minnesota river to a point near the east line of section 33, Odessa, nine miles below Big Stone 

 lake, where, becoming grounded in the channel of the stream, it was abandoned and afterward 

 burned, excepting the bottom of its hull which still remains. It was expected to float this steamer 

 into Big Stone lake and thence into lake Traverse and the Bed river. At the highest floods pro- 

 duced by snow-melting in exceptional years, such a feat may be possible, as the water where the 

 divide between Big Stone lake and lake Traverse would be crossed, close to the east bluff a half 

 mile north of Brown's Valley station, is then three or four feet deep. This water comes mainly 

 from the overflow of the Minnesota river whose banks at Brown's Valley station are a few feet 

 higher than this lowest point of the water-shed. Currents of the flood brought into the valley by 

 the Minnesota river often go thence both to the north and south; but probably no outflow passes 

 southward from lake Traverse into Big Stone lake. 



Modified drift and alluvium. Four to six miles southeast from the north end of Big Stone 

 lake, much of the slightly undulating surface consists of water-deposited gravel and sand, instead 

 of the unmodified glacial drift which prevails elsewhere. 



In Lac qui Parle county modified drift, or alluvium, perhaps filling an ancient water-course, 

 borders Florida creek on its west side in sections 19, 20 and 29, Garfield; where it is a mile wide 

 and extends two miles from north to south, being five to ten feet above the creek and some twenty- 

 five feet below the average hight of the adjoining areas of till. A few miles farther south this 

 creek is again bordered by a similar alluvial area in the east part of sections 5 and 8, Freeland. 

 This depression and its deposits of modified drift lie close east of the low knolls, strown with boul- 

 ders, which form the terminal moraine in Garfield, but appear to extend southward on the west 

 side of the Antelope hills, and may be found to be continuous in this direction to the old water- 

 course which has been described in the report of Yellow Medicine county, crossing AVergeland 

 and Burton townships. 



On the surface of the sheet of till which covers these counties, are rarely found small knolls 

 or short ridges of gravel and sand, five to ten feet above the average hight of their vicinity. 

 These appear to have been brought by streams that descended from the drift-laden surface of the 

 ice-sheet at the epoch of its final melting. Their origin is thus like that of the long ridges of 

 gravel and sand called kames in Scotland and eskers in Ireland. The only typical kame observed 

 in the examination of these counties lies near the state line and southwest corner of Yellow Bank 

 township. It is composed of gravel and sand, and is 10 to 20 feet high and a quarter of a mile or 

 more in length, running approximately from east to west. At its eastern end a more prominent 

 morainic ridge of coarsely rocky till runs from southeast to northwest. 



The bottomland of Brown's Valley, about a mile in width and reaching four miles from lake 

 Traverse to Big Stone lake, is alluvial gravel, sand and silt, along its most depressed portion; but 

 till forms the plateau, about 40 feet above the Minnesota river, close south of Brown's Valley vil- 

 lage, and also, in some places, it forms slopes of moderate ascent next to the base of the bluffs. 

 Along Traverse and Big Stone lakes the bluffs of this valley often rise directly from the lake-shore, 

 leaving no considerable width of bottomland; and the margins of the lakes in some portions is 

 made wholly of boulders, up to six feet in diameter, which form a wall five to eight feet high, 

 piled against the foot of the bluff. An instance of this was seen on the northeast shore of Big 

 Stone lake, close south of William H. Bowman's in section 18, at the west side of Prior. The 

 broadest area of cultivatable bottomland adjoining the northeast side of Big Stone lake is in the 

 fraction of T. 123, E. 47, which makes the southeast part of Prior township. S. P. Lindholm 

 lives on this bottomland, which in sections 11 and 13 has a width of about a half mile, consisting 

 principally of till and ascending by a gradual slope from the edge of the lake to a hight of 40 or 50 

 feet at the foot of the bluff of till, which next rises steeply 75 or 100 feet. At Mr. Jacob Hurley's, 

 in section 19, Big Stone, about five miles north of Ortonville, the surface of moderately sloping till 



