4 SOILS OF THE EASTERN UNITED STATES. 



It is distinguished from the soils of the Marshall series by the pres- 

 ence of stone or gravel in the subsoil and from all other upland soils 

 of the region by its very dark-colored surface soil. 



SURFACE FEATURES AND DRAINAGE. 



The typical areas of the Carrington clay loam occupy nearly level 

 to undulating or rolling upland prairies in the North Central States. 

 In North Dakota especially there are extensive tracts of the type 

 which are almost absolutely level, while in Minnesota, Iowa, and 

 southern Wisconsin the type is more varied in its surface configura- 

 tion, and rolling to sloping surface features are more characteristic. 



In all areas there is usually sufficient surface slope to make natural 

 drainage conditions adequate for cropping, and only in the extremely 

 level or depressed portions of the type, chiefly in small local areas, is 

 artificial drainage required. 



The absolute elevation of this soil above sea level varies with the 

 slope of the low plateau country where it is found. In southern 

 Wisconsin its altitude varies from 700 to 900 feet above tide level; 

 in southern Minnesota and in north-central Iowa its altitude is 

 about 1,000 feet above tide; while in eastern North Dakota it lies at 

 altitudes ranging from 1,100 to 1,300 feet above the sea. This varia- 

 tion in altitude is due to differences in elevation of the underlying 

 rock formations upon which the soil was deposited since it maintains 

 a rather uniform depth of 10 to 30 feet of glacial till from which the 

 soil type was formed. Low ridges, marking the presence of belts of 

 glacial moraine, are found within the type with small depressions 

 between, showing the presence of ponds and lakes now filled. There- 

 are also narrow sloughs and some deeper drainage ways within the 

 areas of this soil. In general there are no serious topographic ob- 

 structions to the complete agricultural occupation of the type ; stones 

 are not usually present in sufficient quantity to hinder cultivation 

 and only local areas require additional drainage facilities. 



The Carrington clay loam is therefore naturally well fitted to sus- 

 tain a prosperous agriculture. 



LIMITATIONS IN USE. 



The textural characteristics of the Carrington clay loam make it 

 especially suited to grass and grain raising, particularly in the 

 northern latitudes within which it occurs. The type is too dense 'and 

 retentive of moisture, particularly in the subsoil, to constitute a 

 special-purpose soil except under unusual conditions. It has, there- 

 fore, been developed properly as a general farming soil in all but a 

 few localities where special market demands have given it a local 

 value for the production of cabbage, onions, and sugar beets. 



