9. POST OAK FLATWOODS. OS" 



9. The Post Oak Flatwoods. 



(Figure 35.) 



This is a very narrow belt, both in Alabama and in 

 Mississippi, the only two states in which it is represent- 

 ed. The Alabama portion has been estimated by Dr. 

 Smith (no. 6, p. 61 ; no. 7, p. 279) to cover 335 square 

 miles. 



References.— Smith 7 (279-281, 460-462, 470), Smith 

 6 (61-62, 128, 129, 132), Smith 8 (188-188, 592-593, 601- 

 602, 609), Smith 9 (132, 188-189, 247-248), U. S. soil sur- 

 vey of Sumter County, and R. D. Webb. 



Geology and soils. — The geological formation of this 

 region is one of the Lower Eocene formations, the Sucar- 

 nochee or Black Bluff, and it forms the surface over 

 most of the area, the Lafayette being apparently absent. 

 The soil to a depth of many feet is a grayish or yellowish 

 laminated or faintly mottled clay, tolerably pure, or at 

 least with very little sand or lime in it. Fresh exposures 

 of it in cuts and ditches soon become covered with fine 

 cracks just like those described on page 72 for one phase 

 of the Tuscaloosa formation. It is fairly well supplied 

 with potash, but deficient in lime and nitrogen, and con- 

 tains a rather high percentage of magnesia, which is be- 

 lieved to be detrimental to some plants. For this reason 

 and also on account of its stiffness, and the scarcity of 

 water, it is not cultivated much. 



Topography and hydrography. — This belt is too nar- 

 row to have any well-marked topographic characters, but 

 it is for the most part pretty level, as its name implies. 

 Small shallow ponds are found in a few places. Some 

 streams flow across it, but few originate in it. 



Forest types. — The forests are nearly all of one type, 

 dry open woods. There are doubtless some characteris- 

 tic trees along the streams, but these have not been stud- 

 ied much. Fires presumably are moderately frequent. 



