THE CLYDE SEKIES OF SOILS. 35 
Niagara County, N. Y., the surface of the type ranges from 300 to 
600 feet above sea level, while in the vicinity of Saginaw Bay, in 
the southern peninsula of Michigan, it lies from approximately 600 
feet to about 750 feet above tide. Other separate areas in southern 
Michigan and northern Indiana have about the same altitude. 
In all cases the Clyde loam is either poorly drained at the present 
time or was poorly drained prior to its occupation for agricultural 
purposes. In practically all areas where it occurs the Clyde loam 
constituted wooded swamps or grass-grown marshes in the days of 
pioneer occupation, and in the majority of instances other upland 
soils were first cleared and occupied. Later the obstructed natural 
drainage was improved by the straightening of streams and the 
opening of drainage ditches, and gradually increasing areas of this 
black mucky soil have been brought under cultivation. The Clyde 
loam in its undrained condition, wherever it is encountered, either 
constitutes swamp not occupied for any agricultural purpose or else 
forms pasture lands upon which cattle are grazed during the later 
months of the summer, or where, in the treeless areas, swamp grass is 
cut for hay. It has only been through the establishment of artificial 
drainage that this soil has been made available for agricultural use. 
Owing to the swampy or semiswampy condition of the Clyde 
loam prior to drainage, the surface soil is frequently found to be 
in a puddled, compact state, sticky and impervious when wet and 
drying out to a clodded or cementlike surface when dry. These 
effects of poor drainage are emphasized where the finer-grained 
material is found in lower lying areas which have been under culti- 
vation for only a short time. In such cases the soil proper is fre- 
quently stiff and sticky and clods badly when plowed. The con- 
tinued cultivation of the type, however, and the long-continued 
operation of frost upon well-drained areas tends to correct this 
condition and to make the Clyde loam an extremely valuable soil 
for the production of the majority of the general farm crops suited 
to the temperate climate within which the type is most extensively 
developed. 
In the case of the Clyde loam a larger acreage of the type is 
devoted to the production of grass for the cutting of hay than to 
any other crop. The type is not only well suited to produce large 
yields, but the management of the soil and of the general farming 
system in the areas where it occurs has brought about a crop rota- 
tion usually consisting of one year devoted to the production of a 
heed crop, one or two years devoted to small grain growing, to be 
succeeded by two, three, or even five years of grass production in 
the course of the rotation. Because of the adoption of such long- 
term rotations, in which the land is frequently occupied during half 
of the entire period by the stand of grass, the acreage of this crop 
