20 BULLETIN 141, U. S. DEPARTMENT OE AGRICULTURE. 



in the different areas from a gray or white sand to a gray silty clay. 

 In almost all cases the surface soil is immediately underlain by a 

 layer of gray or white sand of medium to coarse texture to a depth 

 of 2 or 3 feet from the ground surface. This is, in turn, underlain 

 by a heavier and more silty or claylike deep subsoil which is very 

 retentive of moisture. 



Not infrequently a small amount of fine gravel is found, inter- 

 mingled with both the surface soil and subsoil. It does not usually 

 interfere with the cultivation of the soil and is not so abundant nor 

 so generally present as to make any appreciable difference in the 

 relationships of the soil type to moisture. 



The Clyde sand is always found in level tracts which are de- 

 pressed below the general level of the surrounding uplands and in 

 positions where either glacial outwash or later soil wash from sandy 

 upland areas has accumulated under conditions of poor drainage. 

 There are no elevations or irregularities of surface which would 

 interfere with cultivation. Frequently the areas occupied by the 

 Clyde sand still receive wash from higher lands, and they also re- 

 ceive a considerable amount of seepage water from adjacent porous 

 soils of greater elevation. 



Practically all areas of the Clyde sand are found to be in a swampy 

 condition when first occupied, and many areas have remained unre- 

 claimed by artificial drainage. As a result of this condition large 

 amounts of vegetable matter in a partly decayed state have accumu- 

 lated in the surface soil, rendering it black in color and loamy in 

 texture. Similarly the drab or gray color of the subsoil is an indi- 

 cation of poor natural drainage. The excess water held in the subsoil 

 has excluded the air, and there has been little or no weathering and 

 oxidation of the iron-bearing minerals of the subsoil. Where drain- 

 age has been partly established the subsoil colors are tinged with 

 yellow or brown. 



Wherever the Clyde sand has been occupied for the more intensive 

 forms of agriculture it has been necessary to establish open ditches 

 for the outlets of extensive tile underdrains or in connection with 

 smaller open farm ditches. In its natural condition the Clyde sand 

 supports a thick growth of water-loving trees and of swamp grasses. 

 In such localities its chief economic use is as pasture. Only when 

 artificial drainage has been installed is the type well suited to crop 

 production. 



Where the Clyde sand has been properly drained it has been suc- 

 cessfully occupied for the production of the general farm crops, of 

 which the yields are moderate. Corn is one of the most extensively 

 grown and important crops. The large amount of organic matter 

 in the surface soil, the ease with which a good moisture supply is 

 maintained, and the easy tillage of this soil tend to make it one of 



