THE CLYDE SEEIES OF SOILS. 19 



accumulation has been sufficient to constitute a normal soil rendered 

 dark brown or black at the surface. In the latter cases considerable 

 areas of different soils of the Clyde series have been formed. 



The largest single area of this description occurs in northwestern 

 Indiana and northeastern Illinois along the banks of the Kankakee 

 Iliver. From the southern boundary of Michigan to Will County, 

 111., this river is bounded by a level terrace area which was probably 

 formed as the bottom of a local glacial lake but which has since been 

 drained by the cutting down of the lower reaches of the Kankakee 

 River. The present land surface lies at an elevation from 10 to 30 

 feet above the normal level of the river. The area constituted a 

 vast swamp in the early days, but has been partially drained and oc- 

 cupied. Its surface is only relieved by low ridges of sand which in 

 many instances resemble lake-shore deoosits but in other cases are 

 evidently sand dunes. 



A considerable part of the terraces along the Kankakee River is 

 occupied by the more sandy members of the Clyde series. Other 

 portions consist of muck and peat, of sand dunes, and of undrained 

 swamps. 



There are many other instances where smaller areas of soils of 

 the Clyde series are found within the old glacial terrace deposits 

 along the courses of streams once occupied by a greater volume of 

 water than at present. Certain of these areas of the Clyde series 

 are found far to the south of the glacial lake areas within which 

 the greater part of the Clyde series soils occur. 



Numerous small areas of soils of the Clyde series are also found 

 in depressions throughout the glaciated uplands of western Ohio 

 and northern Indiana. 



TYPE DESCRIPTIONS. 



CLYDE SAND. 



The Clyde sand has only been encountered in the southern penin- 

 sula of Michigan, where five soil survey areas have included portions 

 of this type. By far the largest area, amounting to more than 

 one-half of the total, occurs in Allegan County, Mich. Here the 

 type occupies 38,600 acres, while the total area surveyed in the 

 State amounts to 67,400 acres. It is probable that the extension of 

 soil surveys in this general region will show a much larger total 

 area of the type, occurring in low-lying and poorly drained locations 

 where sandy glacial outwash was accumulated under ponded and 

 swampy conditions. 



The surface soil of the Clyde sand to an average depth of 12 inches 

 or more consists of a medium to fine grained, black, sandy loam, well 

 supplied with partly decayed organic matter. The subsoil varies 



