SOILS DEPOSITED BY WATER 47 



deposited in shallow off-shore water, and subsequently 

 raised above sea-level, where they have been subject 

 to erosion by the present drainage channels, so that 

 they are furrowed by a ramifying system of shallow, 

 steep-sided gorges. These channels reveal the different 

 sorts of material from coarse to fine, and have exposed 

 each of them over considerable areas. The material 

 has not been deposited long enough or buried deep 

 enough to be much consolidated, although there are 

 very soft shales and limestones in the Gulf states which 

 are only partially consolidated. 



18. Lacustrine soils. Closely related to the marine 

 soils are soils deposited in lakes, such as those fringing 

 the Great Lakes. These lacustrine soils differ from the 

 former in the different source of their material and 

 somewhat different conditions of deposition. Most of 

 them are fresh-water bodies, but in some instances, 

 as Great Salt Lake, they are brackish. It is impossible 

 to draw any definite line of distinction between these 

 two sub-groups of soils further than in the extent and 

 character of the waters in which they were deposited, 

 and for a specific understanding of their characteristics 

 the respective types must be studied in detail. 



19. Alluvial soils. Along every stream course is a 

 ribbon of material formed by the deposition from the 

 water of that stream at either normal or flood time. 

 Along the steep-bedded streams it is very narrow and 

 usually coarse, often with a base of stone covered by a 

 veneer of fine material. As the course becomes less 

 steep, it widens and is more meandering. The stream 

 swings from side to side of its valley in large sweeping 



