THE CHEMICAL COMPOSITION OF SOIL. COLLOIDS 9 
12. Dunkirk clay loam. Depth to 10 inches. McLeans, Chautauqua County 
N. Y. Brownish-gray, mellow, friable silty clay loam. Topography gently 
sloping. Drainage fair. 
13. Fallon loam. Depth to 12 inches. Six miles west of Fallon, Churchill 
County, Nev. A dark-gray to nearly black loam. Very impervious to water. 
Topography rolling, though the internal drainage is poor. 
14. Hagerstown loam. Depth to 8 inches. Two miles south of Frederick, 
Frederick County, Md. Brownish-yellow loam. Does not clod when worked 
at the proper moisture condition. The soil occupies undulating areas, which 
are naturally well drained. 
15. Hagerstown loam. Depth 8 to 30 inches. Subsoil of No. 14. A reddish- 
brown, firm, but fairly friable clay. 
16. Houston black clay. Surface soil, Dallas County, Tex. This is the 
black, waxy soil of Texas.. It is exceedingly sticky and gummy. 
17. Huntington loam. Depth to 8 inches. One mile west of Seneca, Mont- 
gomery County, Md. A dark-brown mellow loam carrying a high percentage 
of silt. Sample was taken from a rather high first-bottom area above the 
Potomac. Does not easily clod. Breaks up into good tilth when plowed under 
proper moisture conditions. It is typically Huntington in color and physical 
characteristics, but the material is not all derived from limestone soils, being 
mixed with the wash from upland areas of Chester and associated soils. Sur- 
face drainage excellent. 
18. Huntington loam. Depth 8 to 30 inches. Subsoil of No. 17. A light 
brown silty clay loam of a rather compact but friable structure. 
19. Iredell clay. Depth 6 to 24 inches. Statesville, Iredell County, N .C. 
Brownish-yellow, heavy, plastic, waxy clay. Shrinks and cracks badly when 
dry. Clods badly. Topography level to undulating. Surface drainage poor to 
fair and internal drainage poor. 
20. Lufkin clay. Depth 5 to 36 inches. Three miles west of Starkville, 
Oktibbeha County, Miss. Dark gray in color and waxy and puttylike in tex- 
ture. Clods badly and remains cloddy throughout the growing season. Top- 
ography flat and surface and internal drainage poor. 
21. Manor loam. Depth to 7 inches. Two miles northeast of Wheaton, 
Montgomery County, Md. A very light-brown loam carrying a noticeable 
amount of finely divided mica scales. Topography rolling to hilly. Surface 
and internal drainage good. Does not clod. 
22. Manor loam. Depth 7 to 20 inches. Subsoil of No. 21. Brownish- 
yellow, micaceous loam, with a sufficient amount of finely divided mica to give 
it a slick, greasy feel and a friable structure. In places the subsoil extends 
to a depth of 3 feet, but generally it grades into a disintegrated schist at less 
depths. 
23. Marshall silt loam. Depth to 14 inches. Two miles west of Mynard, 
Case County, Nebr. A dark-brown silt loam, moderately compact, but friable 
in structure and easily crumbled. Nearly black when wet. Slight mottlings 
of a dark bluish gray are faintly discernible in the lower part of the soil. It 
is rather plastic and sticky when wet, but dries out so quickly after rains that 
it permits cultivation without much clodding. Topography as a whole is 
rolling, but at the point where this sample was taken the surface drainage was 
just sufficient to carry off the excess water. 
24. Marshall silt loam. Depth 14 to 36 inches. Subsoil of No. 23. Lighter in 
color than the soil, more compact and contains more clay. From 20 to 24 
inches the subsoil passes into a light-brown or yellowish compact silty clay 
loam, which becomes brownish yellow at 30 to 36 inches. There is a slight 
mottling of grayish streaks where the color becomes pronounced brownish 
yellow. 
25. Miami silty clay loam. Depth to 10 inches. Jefferson, about 20 miles 
southwest of Fort Wayne, Wells County, Ind. Light grayish brown when wet. 
In texture a friable silty clay loam to a depth of 7 inches, below which there 
appears to be more clay and the soil is more plastic. If plowed when wet, 
considerable clodding occurs, but in conditions of normal moisture the soil 
works well. Topography gently sloping, with good surface drainage. 
26. Miami silty clay loam. Depth 10 to 24 inches. Subsoil of No. 25. 
Yellowish-brown compact silty clay loam. Contains some mottling of light 
gray and an occasional lump of blue clay 2 to 4 inches in diameter. At 30 
inches and below there is an accumulation of calcium carbonate and fragments 
of limestone. 
10875—24 2 
