YELLOW MEDICINE, LYON AND LINCOLN COUNTIES. 595 



Soil and timber.] 



1500; T. 110, R. 43, 1625; and Shelburne, 1700. The mean elevation of 

 Lyon county is thus about 1320 feet, or a quarter of a mile, above the sea. 

 In Lincoln county the greatest elevation is the top of the outer moraine 

 west and south of lak-e Benton, 1950 to 1975 feet above the sea, and about 

 200 feet above this lake. The lowest land of the county is near its north- 

 east corner, where the Yellow Medicine river crosses the east line of Alta 

 Vista, about 1175 feet above the sea, or 800 feet below this crest of the 

 Coteau des Prairies, twenty-five miles distant in the southwest part of the 

 county. At the southwest corner of Lake Benton township, where the 

 channel that extends south from the " Hole in the Mountain" is crossed by 

 the county line, its hight is about 1675 feet, being some 90 feet below its 

 highest point, which is a mile southwest from Lake Benton. The mean 

 hights of the townships of Lincoln county are nearly as follows: Alta Vista, 

 1325 feet above the sea; Limestone, 1600; Lake Stay, 1700; Marshfield, 1750; 

 Hope, 1775; Marble, 1550; Royal, 1700; Ash Lake, 1760; Diamond Lake, 1800; 

 Lake Benton, 1850; T. 113, R. 46, 1725; Hendricks, 1775; Shaokatan, 1825; 

 Drammen, 1875; and Verdi, 1850. According to these estimates the mean 

 elevation of this county above the sea is approximately 1725 feet. 



Soil and timber. The soil throughout this district is almost everywhere the somewhat stony 

 and gravelly clay of the unmodified glacial drift. Vegetable decay has enriched this and colored 

 it black to a depth that averages about two feet, but varies from one to four feet, being greatest 

 in depressions and least upon swells or knolls, especially on the hillocks and small ridges of the 

 moraines. Below this soil the drift, mainly consisting of the same boulder-clay, extends from 

 fifty to a hundred or two hundred feet in depth, being yellowish and usually soft enough to be 

 dug with a spade for a thickness of ten or twenty feet, and thence dark bluish and harder, re- 

 quiring to be picked. This deposit, called till, is made up of the materials gathered during the 

 ice age from near and remote portions of a large district northward, mingled and spread in an 

 unstratified mass, which nearly everywhere is principally clay, but also includes considerable pro- 

 portions of sand and gravel, and occasional boulders. The majority of its large boulders are 

 granite and gneiss, while most of its clay is probably derived from Cretaceous beds of clay and 

 shale. Magnesian limestone, occurring in fragments, from blocks ten or fifteen feet in diameter 

 to the smallest pebbles, and pulverized, forming then an indistinguishable part of the till, is one 

 of its most important ingredients in this region and through all western Minnesota. Dissolved 

 in the waters of wells and springs, it makes them hard, diminishing their desirability for wash- 

 ing and for use in the boilers of steam-engines, but not for drinking and cooking. On the other 

 hand this element contributes a large share toward making the very fertile soil of this district, 

 and producing the magnificent harvests of wheat, which are its principal export and source of 

 wealth. 



Much of the water that falls as rain is absorbed by the land and is gradually given up to 

 growing crops; while the surplus waters of heavy rains and of snow-melting in spring are soon 

 drained away by the undulating slopes of the surface, and by its many water-courses. Here and 

 there, however, on the approximately level parts of the district, frequent shallow depressions, 

 mostly of small area, are left without outlet and continue marshy till the driest season or through 

 the whole year. These wet tracts, which are called sloughs, bear luxuriant grass, and are valu- 

 able for their hay, the yield of which is from two to three tons per acre. 



