MARINE AND LACUSTRINE SOILS 



21 



Low ranges and hills consisting of "glacial tiir' or "bowlder 

 clay^^ were brought into existence. At this time, too, numerous 

 lakes were formed, many of which have long since filled up or 

 disappeared. "Rolling" topography and scattering bowlders of 

 all sizes and kinds are other characteristics of a glaciated country 

 (Figs. 10 and 11). 



Quality of Glacial Soils. — In general, glacial soils have wide 

 variations; many are comparatively "heavy,'' hence silt and clay 

 loams are common. Some are very stony (Fig. 12), and many 

 are. in need of drainage. Great variations exist as to their 

 agricultural value. 



Fig. 12.^The inside of some of the glacial deposits. This deposit consists of very stony 

 and gravelly glacial till. Wisconsin. (King.) 



Marine and lacustrine soils are soils derived from material 

 accumulated on the sea bottom and in glacial lakes, respectively. 

 The coarser and heavier particles settled to the bottom near shore, 

 and the finer silt and clay were carried out into deep water. These 

 deposits vary in thickness, and in case of marine deposits particu- 

 larly, commonly consist of layers of coarse and fine material. 

 Because of changes in the earth during the past ages — such as the 

 disappearance of old lakes and rise in land elevations, much of this 

 material deposited in the sea and lakes during ages past has 

 become exposed and is now called marine or lacustrine soil as the 

 case may be. Nearly all the soils of the Atlantic and Gulf Coastal 

 Plains are of marine origin. They are especially adapted to the 

 growing of cotton, corn, peanuts, melons and fruit. 



