SOILS AND FERTILIZERS 319 



rolling, but in the broad southern extension, where the seaward slope 

 is hardly more than 1 foot to the mile, drainage is apt to be de- 

 ficient. Here rain water often remains upon the surface for a con- 

 siderable time, although the conditions are not comparable with 

 those of a true swamp. The soils in this level section, while com- 

 posed largely of sand, are compact, usually deficient in organic mat- 

 ter, and not very productive. Many of the flat interstream areas 

 possess such poor, drainage that true swamps, such as the Dismal and 

 Okefenokee, have been formed. Near the coast and along the tidal 

 estuaries extensive marshes, separated from the ocean by sand bar- 

 riers, are found. 



The Coastal Plain is made up of unconsolidated gravels, sands, 

 and sandy clays, with less frequent beds of silts and heavy clays. 

 The deposits on the Atlantic coast have been derived mainly from 

 the erosion of the Piedmont Plateau and other inland areas, while 

 the deposits on the Gulf coast have been derived mainly from trans- 

 ported glacial material and from western plains. The materials have 

 been transported and deposited beneath the sea and subsequently ex- 

 posed by the uplift of the ocean floor. In the more northern parts of 

 the Coastal Plain, and even as far south as Virginia, the character of 

 the deposits has been modified by glacial action and the flooded con- 

 dition of the streams resulting from the melting of the ice. 



The Coastal Plain deposits range in age from Cretaceous to Re- 

 cent. Although extensive areas of the older sediment are exposed 

 at the surface to form soils, still by far the greater part of the ma- 

 terials is Quarternary or Recent in age. 



The soils are for the most part composed of sands and light sandy 

 loams, with occasional deposits of silts and heavy clays. The heavy 

 clays are found principally near the inner margin of the Coastal 

 Plain. The silts, silty clays, and black calcareous soils, upon which 

 the rice and sugar cane industries of southern Louisiana and Texas 

 are being so extensively developed, have no equivalents in the Atlantic 

 division. 



Bastrop Series. This embraces four types of soil sandy loam, 

 fine sandy loam, silt loam, and clay. They are brown in color, and 

 are found only in Texas. Cotton, corn, sorghum, alfalfa, melons and 

 potatoes are successfully cultivated. 



Crockett Series. This, also found in Texas alone, comprises 

 four types gravelly loam, fine sandy loam, loam, and clay loam. 

 The soil is gray to dark gray, sometimes almost black in color. The 

 clay loam yields cotton above the average, and is used for general 

 farming purposes; the gravelly loam is adapted to early vegetables 

 and trucking. 



Elkton Series. This consisting of sandy loam, fine sandy loam, 

 loam and silt loam, is of a light gray to white. Some types of this 

 series are found in Delaware, Maryland, New Jersey, Pennsylvania 

 and Virginia. The series is best suited to grass and forage crops. 



Gadsden Series. This is composed of three types sand, sandy 

 loam and loam. The soils are found in Florida, Georgia and Mis- 

 sissippi. The sand is very productive, and of special use in growing 



