SOILS AND FERTILIZERS 331 



ness from a few feet to more than 300 feet. Often this material has 

 been transported hundreds of miles, and is wholly unrelated to the 

 underlying rocks, but in some places the movement has been slight, 

 and the drift consists very largely of the ground-up underlying rock. 

 Over a large proportion of the area covered by the drift and also along 

 the Ohio and Mississippi rivers and in Kansas and Nebraska the sur- 

 face material consists of a fine silty deposit, known geologically as 

 loess and plains marl. In the classification of the glacial soils three 

 important series Miami, Marshall, and Volusia having distinct 

 characteristics have been recognized, and, in addition, quite a num- 

 ber of miscellaneous soils which can not be put in any series. 



Marshall Series. This includes the dark colored upland glacial 

 and loessial soils which cover almost all of the great prairie region 

 of the central West. They are of a dark brown color. The topog- 

 raphy is level to rolling. These soils are very productive and con- 

 stitute the great corn soils of the country. The Marshall silt loam, 

 loam, and clay loam constitute the principal soil types throughout the 

 great corn belt and rank among the most productive of our general 

 farming soils. In Iowa, Illinois, and Nebraska corn, oats, clover, 

 and timothy are the leading crops, while in Minnesota and the 

 Dakotas wheat is of primary importance. 



Miami Series. This is one of the most important, widely dis- 

 tributed, and complete soil series that has been established. The 

 series is characterized by the light color of the surface soils, by deriva- 

 tion from glacial material, and by being timbered either now or origi- 

 nally. The heavier members of the series are better adapted to wheat 

 than the corresponding members of the Marshall series, but they do 

 not produce as large yields of corn. 



The clay loam is the most important for general farming, and 

 forms the principal type of soil in western Ohio and central and east- 

 ern Indiana. It is especially well adapted to small grain and grass 

 crops. The silt loam is more rolling and hilly than the clay loam 

 and is not so well-suited to general farming. Wheat does better upon 

 it than upon the Marshall silt loam, with which it is closely asso- 

 ciated, but the yields of corn are considerably less. It is also well 

 adapted to fruit, especially apples. The sandy loam and fine sandy 

 loam are used for general agriculture, but are especially adapted to 

 medium and late truck crops and fruit. The loam is suited to corn 

 and potatoes, while small grain and grass are grown, but with less 

 success than upon the clay loam. Strawberries and raspberries, as 

 well as other small fruits, do well on this type. The stony sand, 

 gravelly sand, and gravel are not of much agricultural value under 

 present conditions. The stony loam is a good general farming soil, 

 is also well adapted to apples, and furnishes excellent pasture, while 

 in New York alfalfa is grown upon it very successfully. The stony 

 sandy loam and gravelly sandy loam are not strong soils, but are 

 fairly well suited to light farming, fruit, and truck. The sand and 

 fine sand are not adapted to general farming, but are the best early 

 tmck soils of this section. 



