4 SOILS OF THE EASTERN UNITED STATES. 



loam in the majority of the areas where it has been encountered is 

 stone free and even gravel is lacking. It is only in marginal areas 

 or in locations where the surface covering of typical Clyde loam is 

 somewhat thin that the stone or gravel of underlying glacial forma- 

 tions becomes evident. In Niagara County, N. Y., a phase of the 

 type, which constitutes only a thin covering over underlying glacial 

 material, is marked by stone and bowlders over its surface. This, 

 however, is unusual. 



The Clyde loam is separable from the other members of the Clyde 

 series because of its different texture, being considerably more stiff 

 and plastic than the sandy loam and possessing a loamy covering 

 over the stiff clay which characterizes the Clyde clay loam or clay. 



The Clyde loam differs from the members of the Fargo series, 

 also of glacial-lake origin, in that the latter are decidedly and dis- 

 tinctly calcareous in the subsoil in all areas where they have been 

 encountered, while the Clyde loam is not so characterized. It differs 

 from the soils of the Carrington series, in that the latter possess the 

 bowlder clay or till subsoil characteristic of that series. 



Thus the Clyde loam and its associated soils of the series may be 

 readily distinguished from other dark-colored or black soils of the 

 general region. 



SURFACE FEATURES AND DRAINAGE. 



The Clyde loam invariably occupies level or depressed areas 

 which at some previous time have constituted the beds of glacial 

 lakes or of large swamps. Such areas occur not only within the re- 

 gions formerly occupied by extensions of Lakes Erie and Huron, 

 but also in the beds of many smaller extinct glacial lakes which 

 were ponded between the inequalities of the rolling to ridged glacial 

 drift. In all instances the mineral matter from adjoining uplands 

 was washed down and deposited in the form of fine or coarse sedi- 

 ments within these small or large lake beds, and as the water became 

 shallower, vegetation gained a foothold, giving rise to the incorpo- 

 ration of large amounts of mucky or peaty organic remains within 

 the zone which now constitutes the surface soil. 



The surface of the Clyde loam is almost invariably level, although 

 in some areas low. rounded knolls and gentle swells within the gen- 

 eral area of the ancient lake beds may also be covered by the same 

 characteristic mucky, swamp deposits. In all cases the area of the 

 Clyde loam is distinctly depressed below the level of adjoining 

 glaciated uplands and glacial moraines or below the level of the 

 marginal glacial-lake deposits. 



The altitude of the surface of the Clyde loam varies considerably 

 in the different areas where it has been encountered. Thus in 

 western New York, in Niagara County, the surface of the type ranges 



