SOILS OF THE EASTERN UNITED STATES AND THEIR USE XIII. 



THE MEMPHIS SILT LOAM. 



GEOGRAPHICAL DISTRIBUTION. 



The Memphis silt loam consists of finely divided silty material, 

 known as the loess, which had its origin in the more northern por- 

 tion of the central States in conjunction with the glacial invasion 

 of that section. Unlike the other soil types derived from the loess, 

 however, the Memphis silt loam is derived from those deposits that 

 extend southward from the confluence of the Missouri and the 

 Mississippi Rivers almost to the margin of the Gulf of Mexico. 

 In this respect it is unique among loess-derived soil types. This 

 material, originated in connection with the glaciation of the North 

 Central States, was carried southward by the waters resulting from 

 the melting ice, and distributed along the drainage ways through 

 the Mississippi Valley. Thence, it is supposed that a considerable 

 proportion of the material has been reworked and redistributed, 

 through wind action, being deposited principally upon the eastern 

 side of the Mississippi River, from the vicinity of St. Louis, Mo., 

 southward to Baton Rouge, La. It thus comprises a long nar- 

 row belt along both sides of the Mississippi River in southern Illi- 

 nois and eastern Missouri, covering a considerable proportion of 

 the upland in western Kentucky, a belt 50 to 70 miles broad in 

 western Tennessee, a continuous belt, varying from 50 miles in width 

 in northern Mississippi to a narrow strip, 15 to 20 miles broad, where 

 it passes across the southern line of Mississippi into eastern Louisiana 

 and terminates between Baton Rouge and New Orleans. It also 

 occurs covering a considerable territory on the west side of the 

 Mississippi in northeastern Arkansas. 



Throughout its entire extent this characteristic glacial silt was 

 carried far southward by water action, from a truly glaciated region, 

 and distributed by the action of both wind and water principally 

 over the uplands to the east of the Mississippi River. It covers the 

 various Coastal Plain formations and, in its more northern portion, 

 even the consolidated rocks of the outward edge of the Ozark uplift. 



The Memphis silt loam has been mapped to the extent of 

 1,863,290 acres. It has been encountered in 12 separate areas in 6 



different States. 



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