THE CLYDE SERIES 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 
River. 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,G00 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 
