6 BULLETIN 659, U. S. DEPARTMENT OF AGRICULTURE. 
SOILS. 
The 13 soil types found in Ellis County vary from fine sand to 
stiff clay. Most of these soils are derived from marls and chalky 
limestones. The geological formations known as the Taylor Marl 
and xVustin Chalk are the sources from which the Houston black 
clay is derived. The farms studied in this analysis are practically 
all located on this soil type (see map, fig. 2), and consequently a 
somewhat detailed description of this type is given. 
The Houston black clay occupies more than one-third of Ellis 
County. The surface soil, to a depth of 10 inches, is very heavy, 
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SOIL MAP 
U. S. BUREAU of SOILS 
Houston b/ach clau "Black land. " 
It soil types other than "Black land- " 
Location of farms*Yvhere records were rahen. 
Fig. 2. — Map of Ellis County, showing soils and location of farms studied. 
tenacious black clay. The subsoil has practically the same charac- 
teristics as the soil, although it is a little lighter in color, owing to 
a smaller percentage of organic matter. 
The type is locally known as " black land." When dry and well 
cultivated it is very friable and easily worked. When plowed too 
wet it forms clods, but after they have been exposed to the weather 
for some time they break down to a certain degree and the soil can 
be put into good mechanical condition again by means of a light 
harrow. If not tilled the soil cracks badly in dry weather; some- 
times the cracks are several inches wide and several feet in depth. 
