YELLOW MEDICINE, LYON AND LINCOLN COUNTIES. 593 



Antelope hills and valley. Coteau des Prairies.] 



In western Yellow Medicine county, a few miles northeast from Canby and the Winona & 

 St. Peter railroad, we find another rolling belt, more broken and irregular in contour than the 

 preceding, with steeper knolls and short ridges, from 15 or 20 to 40 or 50 feet in hight, but oc- 

 cupying a narrower area, which varies from an eighth of a mile to one mile, or at the most only 

 two or three miles, in width. These drift accumulations consist of till, with many boulders, and 

 appear to be a terminal moraine, heaped along the border of an ice-sheet. They extend in a con- 

 tinuous series, from near the south line of Yellow Medicine county, northwesterly to the Ante- 

 lope hills in Lac qui Parle county, and onward through that county into Dakota. At the west 

 side of this low range of knolly and hilly drift, between it and the massive highland of the Co- 

 teau des Prairies, there intervenes a belt of smooth, slightly undulating till, three to six miles 

 wide, called the Antelope valley. This is part of the undulating area, approximately a plain, 

 that rises imperceptibly from the Minnesota river to the Coteau; and its somewhat valley-like 

 appearance is due to its being separated from the broad eastern part of this expanse by the 

 moraine, which attains a hight 25 to 100 feet above the general level, culminating in the Antelope 

 hills. 



The Coteau des Prairies. A large area extending from southeast to northwest through 

 southwestern Minnesota, including the southwest half of this district, lias an elevation from 500 

 to 1000 feet above the Minnesota river, and from 1300 to 2000 feet above the sea. Upon this 

 highland are the sources of Lac qui Parle, Yellow Medicine, Redwood and Cottonwood rivers; 

 of the Des Moines river; and of the Little and Big Sioux rivers, tributary to the Missouri. This 

 elevated tract, throughout its course of two hundred miles, was called by the earliest French 

 explorers the Coteau des Prairies, meaning the Highland of the Prairies. Nicollet applies this 

 name to an area ten to thirty or forty miles wide, its width through this district being twenty to 

 thirty miles. 



This highland may be described, in general, as a long plateau or massive ridge, in part 

 smoothly undulating or rolling in contour, but having two belts (terminal moraines) which are 

 very irregularly broken by steep hills, knolls, and small ridges, 25 to 100 feet above the in- 

 tervening hollows. If we except the massive ridge of red quartzyte in northern Cottonwood 

 county, no exposure of the bed-rock is known along the entire extent of the Coteau des Prairies, 

 and its surface everywhere is a thick sheet of the unstratifled glacial drift, called till or boulder- 

 clay. On its smooth areas this deposit has few boulders; but in the two roughly hilly belts it has 

 very abundant boulders and increased proportions of gravel and sand.* 



Elevations, Winona & St. Peter division, Chicago & Northwestern railway. 

 From John E. Blunt, engineer, Winona. 



Miles from Feet above 

 Winona. the sea. 



Tracy 226.55 1403 



Amiret 233.65 1283 



Marshall 243.85 1174 



Grandview '. . . .250.75 1173 



Minneota 256.52 1179 



Canby 274.03 1243 



Gary 284.62 1484 



Elevations, Dakota Central railway. 



Tracy 226.55 1403 



Balaton 239.55 1528 



Redwood river 246.60 1592 



Redwood bridge 246.60 1631 



Tyler 253.70 1750 



Lake Benton, station 261.50 1759 



Lake Benton, water 261.50 1754 



Summit, grade 262.50 1762 



Depression, grade 265.50 1715 



Verdi ..267.60 1771 



*For Nicollet's description of the Coteau des Prairies, see p. 68; compare also pp. 494, 519. 539 and 544: and for a 

 efull discussion of both its topographic and geologic features, consult a later part of this chapter. 



38 



