THE PIEDMONT REGION. 143 



No. 16 is from an uncleared blackjack flat, a short distance east of Ches- 

 ter Court House, considered worthless. No. 17 is from a field of J. B. 

 Stokes, southeast of Chester Court House ; the land roHing blackjack, 

 having on it a crop of about 1,200 pounds of seed cotton to the acre. 

 The soil and subsoil taken uniformly, to the depth of twelve inches in 

 both instances. , The dioritic and felsitic porphyries of Abbeville, pro- 

 duce a soil known there as the " flat woods." They are found in Cal- 

 houn's Mills, Magnolia, Abbeville, Smithville, and Ninety-Six townships, 

 of Abbeville county. Formerly, when more capital and skill was em- 

 ployed in agriculture, these lands were very highly esteemed. Since a 

 cheap and easy, not to sa}'- thriftless, culture has superseded other hus- 

 bandry, they are neglected. (For more particular description see Cal- 

 houn's Mills township. Abstract of Correspondents.) Mr. Tuomey gives 

 the following analyses of these soils. 



(18) (19) (20) 



Organic matter 9.20 10.05 3.40 



Silica 52.00 48.30 53.00 



Alumina 22.10 19.36 19.30 



Oxide of Iron 9.00 8.40 14.10 



Lime 2.50 4.00 1.80 



Magnesia trace. 0.00 0.50 



Potash and soda 0.40 0.90 trace. 



Phosphate of lime 0.00 0.10 0.00 



Water and loss 4.80 8.89 7.90 



100.00 100.00 100.00 



No. 18 is from a well cultivated place north of Calhoun's Mills ; No. 

 19, ditto, near Ninety-Six ; No. 20 is from abandoned lands in the meadow 

 woods of Union. 



These analyses are indicative of the chemical changes that affect the 

 productiveness of these soils. The abandoned field in Union showing a 

 great falling off in organic matter, lime and potash, due to insufficient 

 drainage and a thriftless culture, at the same time there is a large increase 

 of iron, arising doubtless from the absence of those acids resulting from 

 the decomposition of organic matter, wdiose office it is to dissolve and 

 carry off the injurious excess of the salts of this metal. The large amount 

 of lime in all these Trappean soils will be noted, it has induced some 

 writers to classify them as calcareous soils, and adapts them peculiarly 

 for the growth of pea-vines and clover, which thrive almost spontane- 

 ously uj)on them. 



