THE CLYDE SERIES OP SOILS. 43 



from 10 to 15 tons per acre, onions 400 to 700 bushels per acre, while 

 potatoes, which are also grown to a small extent, give yields from 150 

 to 250 bushels per acre. An excellent field of cabbage, grown on the 

 Clyde clay loam, is shown in Plate III, figure 2. 



Elsewhere the Clyde clay loam, where appearing in small areas 

 scattered through other soil types, is either tilled to the general farm 

 crops or, where occurring in larger areas, is utilized mainly for 

 pastures. 



CLYDE CLAY. 



. Next to the Clyde loam the Clyde clay is the most extensively de- 

 veloped soil type of the series. It has been encountered in eight 

 different soil-survey areas, located in New York, Ohio, Indiana, Illi- 

 nois, and Michigan. A total area of 319,424 acres has been mapped, 

 of which considerably more than one-half is found in the soil sur- 

 vey of the Toledo area, Ohio, where 165,056 acres occur. It is prob- 

 able that other large areas will be encountered in the Maumee basin 

 and in the area of glacial Lake Saginaw, not yet covered by soil 

 surveys. 



The surface soil of the Clyde clay, wherever it has been encoun- 

 tered, is characteristically a dark-gray, drab, or nearly black clay 

 loam. It is well filled with organic matter to a depth of 8 or 10 

 inches, and this renders the surface soil considerably more friable 

 and easily worked than would ordinarily be the case with material of 

 such fine texture. There is usually a strong tendency toward granu- 

 lation of the surface soil, due to the .high amount of organic matter 

 contained and to the fact that both the soil and subsoil are some- 

 what calcareous. The subsoil to a depth in excess of 36 inches is a 

 lighter gray, drab, or mottled yellow and gray clay. It is dense and 

 sticky when wet, but becomes intersected with numerous joints and 

 crevices when properly drained and exposed to the action of the 

 atmosphere. It frequently contains gravel, the quantity varying 

 from a few scattered pebbles to a considerable percentage of the soil 

 mass. Neither the soil nor the subsoil contain any considerable 

 number of stones of larger size. In other cases it is free from any 

 trace of gravel and stone and consists of laminated or massive lake 

 clay. In the former instance it is probable that the type constitutes 

 merely a thin surface veneering of glacial lake or swamp material 

 over the underlying till or water-laid glacial deposits. In the latter 

 it is a true glacial-lake deposit. 



In all cases the surface soil gives the distinctive evidences, through 

 the color and the accumulation of organic matter, of the swampy con- 

 dition under which it was formed. 



It is a common characteristic of the Clyde clay, possibly more 

 general than with other soils of the series, that the subsoil contains 



