YELLOW MEDICINE, LYON AND LINCOLN COUNTIES. 605 



Second and third moraines.] 



The second terminal moraine of the last ice-sheet, which is the eastern or inner belt of knolly 

 and hilly drift upon the Coteau des Prairies, extends northwesterly in a nearly straight course from 

 the Blue mounds near Windom, in southern Cottonwood county, to Gary in the edge of Dakota. 

 In Lyon county its northeast boundary passes through the center of Custer, Lyon and Island Lake 

 townships, and follows approximately the line between this and Lincoln county for the next six 

 miles, at the west side of Nordland. It crosses northeastern Lincoln county from the southeast 

 corner of Alta Vista to section 3, Marble, six miles south of Canby; and in Yellow Medicine 

 county its course is from section 33, Norman, to section 7, Florida. The most rough and hilly 

 part of this moraine is from a half mile to one and a half miles wide at its northeast side, where it 

 usually has many irregular knolls, short ridges, and hills, which rise from 25 to 50 feet, and occa- 

 sionally 75 to 100 feet above the intervening depressions. Their conspicuous appearance, as seen 

 from the northeast, is due to the ascent westward of the country upon which they lie. From the 

 specially hilly northeast margin of this morainic belt its width reaches five to fifteen miles south- 

 westward with a rolling and in some places knolly or hilly surface, including the greater part of 

 the distance to the parallel outer range of drift hills, but leaving next to that a smooth, slightly 

 undulating tract, three to five miles wide. In Marslifield and Lake Stay this smooth contour 

 extends eight miles north from Cottonwood lake and the east end of lake Benton, its limit being 

 here twelve miles from the outer moraine. All these areas are till, with abundant boulders upon 

 the portions which are most broken by knolls, hills, and hollows. 



A third terminal moraine, consisting of knolls, hills, and short ridges of till, 15 to 50 and 

 rarely 75 or 100 feet high, with many large and small rock-fragments, is found in Yellow Medicine 

 and Lac qui Parle counties, lying eight to twelve miles northeast from the inner morainic belt of 

 the Coteau, and extending north-northwest forty miles within the limits of this state, beyond 

 which it continues with the same course in Dakota. The width of this morainic series in Minne- 

 sota is usually from a quarter to a half of a mile, being less than that of the specially knolly belts 

 upon the Coteau des Prairies. It appears like them to have been accumulated at the margin of 

 the ice-sheet of the last glacial epoch; but its location shows that it belongs to a later time in this 

 epoch, after two distinct recessions of the ice. From sections 32, 29 and 19, of Burton, this forma- 

 tion continues through sections 13, 11 and3, of VVergeland, with similar outlying hillocks and ridges 

 in sections 9, 15, 16, 21, 22 and 23, of this township; and for the next six miles northward it lies in 

 the southwest edge of Oshkosh and the northeast edge of Hammer. In the south part of Lac qui 

 Parle county it forms the two conspicuous clusters of the Antelope hills, in sections 27 and 16, 

 Freeland, elevated 40 to 100 feet above the smoothly undulating till of that region. 



The southeastern continuation of this third moraine may be represented by the rocky drift 

 knolls, 10 to 20 feet high, which occur about the north end and at the northeast side of lake Mar- 

 shall, in a region which has mainly a very smooth contour. Again, twelve miles farther to the 

 east-southeast, a belt of typically morainic knolls, about twenty rods in width, and a half mile or 

 more in length, was noted close south of the Cottonwood river, in sections 14 and 15, Gales, in 

 Kedwood county. It is probable that a connection southeastward may be found, along some line 

 of more or less knolly and hilly drift, including these two localities and the morainic tract in 

 Stately, Brown county, to the belt of morainic deposits that extends from Fairmont in Martin 

 county southeast to Pilot mound in the northeast corner of Hancock county, Iowa. This view 

 was suggested to me by Prof. T. C. Chamberlin, state geologist of Wisconsin, who first pointed 

 out the continental extent of these terminal deposits of the ice-sheet. 



Professor Chamberlin has also suggested* that these first, second and third terminal mo- 

 raines may be named respectively the Altamont, Gary and Antelope moraines (see fig. 48, page 601). 



The Antelope valley. Between the third or Antelope moraine and the foot of the Coteau des 

 Prairies on the west is the Antelope valley, so named by the Sioux. This is a broad shallow 

 depression, or rather a part of an inclined plane (page 593), with a slightly undulating surface of 

 till, being three to ten miles wide, and reputed to extend a hundred and twenty-five miles, from 

 Minneota, in the most northwest township of Lyon county, to the south bend of the Sheyenne 

 river in Dakota. The moraine of the Antelope hills and the smooth area of till on its east side 

 average 25 to 50 feet higher than the adjoining eastern border of the Antelope valley, but have 

 some lower portions, allowing streams to cross both the valley and the moraine in their northeast- 

 ward course from the Coteau to the Minnesota river. 



*Third annual report of the U. S. geological survey, 1883. 



