10-1 ECONOMIC BOTANY OF ALABAMA. 



507, 515-518, 530-533), Smith 8 (107-117, 120-121, and 

 county descriptions), Smith 9 (284-286, 298-302), Tuo- 

 mey 1 (154-159), Tiiomey 2 (249-252, by E. Q. Thorn- 

 ton). 



Geology and soils. — The principal rock of this region is 

 the Vicksburg or St. Stephens white limestone, regarded 

 by some geologists as the uppermost member of the 

 Eocene and by others as Lower Oligocene; a matter of 

 classification which does not particularly concern the 

 geographer. Some older Eocene rocks, such as Claiborne 

 and Buhrstone, are exposed in the Hatchetigbee anti- 

 cline of Choctaw, Clarke and Washington Counties, 

 which belongs geologically with the region last de- 

 scribed, but for geographical purposes is best included in 

 the lime hills region, which completely surrounds it. The 

 white limestone crops out on hillsides in many places, 

 and is a favorite material for chimneys, on account of 

 the ease with which it can be sawn into blocks of the de- 

 sired size when freshly quarried. 



The soil on the uplands is mainly a dark red loam, 

 probably most of it residual from the limestone, rather 

 than belonging to the Lafayette formation. Like most 

 calcareous soils lying considerably above sea-level, it is 

 very fertile ; except that potash is a little deficient on the 

 ridges. 



The existence of deposits of salt, alkali, sulphur, etc., 

 in this region, especially ih the vicinity of the Hatche- 

 tigbee anticline, is shown by the occurrence of these sub- 

 stancs in the water of springs and artesian wells; and 

 there are a few places where their effects on vegetation 

 are noticeable. 



Topography and hydrography. — The topography is in 

 general rather hilly. In some places in the vicinity of 

 the anticline above mentioned it is almost as mountain- 

 ous as in neighboring parts of the red hills region. One 

 or two caves are reported, but there seems to be no ponds 

 or large limestone springs, and the streams present no 

 peculiarities worth mentioning. 



Climate. — The weather records from Bermuda, Cone- 

 cuh County, which is just about on the northern edge of 

 this belt, may be taken to illustrate its climate. The av- 



