4 BULLETIN 181^ U. S. DEPARTMENT OF AGEIGULTUEE. 
Numerous creeks and ravines drain into the river; these vary in 
size from streams with watersheds of 150 square miles to those 
draining but one or two square miles. Figure 2 (in pocket at end of 
bulletin) shows the location and extent of each of these tributaries. 
Their channels, though smaller, are similar to that of the river. 
CLIMATE. 
The climate is typical of that of the Gulf States. Frequently 
during the summer the temperature reaches 95° F. and maintains 
that height for a considerable length of time. The winters are 
usually mild, and it is very seldom that the temperature falls to zero. 
The records of the United States Weather Bureau at the Yazoo City 
station show a maximum temperature of 107° and a minimum of 
— 2°, with a mean annual temperature of 65°. 
The mean annual precipitation during the past 12 years was 48.1 
inches. The rainfall is well distributed throughout the year, the 
least occurring during the cotton-picking season of September, 
October, and November. A more extensive discussion of rainfall 
will be found in the section of this report dealing with run-off (p. 7). 
AGRICULTURAL CONDITIONS. 
Throughout the Big Black bottoms the soil is very uniform in 
character, being composed of a silty loam underlain by clay. The type 
is called ^'meadow" by the United States Bureau of Soils and is de- 
scribed by the bureau as follows : ^ 
The surface few inches of the material composing the meadow consists of a brown 
or drab silt loam. This is underlain by a drab, gray, or bluish silt or silty clay. In 
local areas and especially near streams there is considerable sand present in both 
soil and subsoil. * * * The type is still in process of formation, each successive 
flood bringing with it material that is left as a thin deposit over the bottoms. The 
soil is very rich, and if cleared, ditched, and diked would be capable of producing 
large yields. At present it is of value only for its timber and the pasture it affords. 
The soil of the uplands is largely a brown or light brown loam, 
underlain by a brown clay. It is considered fertile, but is very easily 
eroded. 
The bottoms, which are at present unsuitable for tillage, were 
originally covered with a heavy growth of timber consisting of water 
oak, black and sweet gum, sycamore, beech, and some cypress. The 
greater part of the valuable timber has been cut, and a second growth, 
together with a heavy stand of cane, brush, and briars, now covers 
the bottoms. With regard to lands bordering streams in Mississippi, 
it is generally recognized that heavy growths of timber indicate 
lasting productiveness of the soil, and that rank growths of under- 
brush, cane, and vines, such as occur in these bottoms, are seldom 
found on poor land. 
1 U. S. Dept. of Agr., Bureau of Sofls, Soil Survey of Holmes County, Miss., 1909. 
