112 THE RED HILL KEOIOX. 



3d. Masses of buhr-stone, composed of silicified shells and other organic 

 remains of the eocene. Among these shells gasteropoda predominate, 

 which, together with the presence of land shells, and shells of mollusks 

 which live in marshes(Auriculae), indicate the literal character of the for- 

 mation. The leaves of oak, beech and willow trees, silicified or converted 

 into lignite, were found here by Mr. Tourney. On Cedar creek, in Aiken 

 county, there arc beds of buhr-stone thirty feet in thickness, and at several 

 points between this locality and the Savannah river on the west, and the 

 San tee and Congaree on the east, there are extensive outcrops of this mate 

 rial, from which mill-stones of excellent quality, equal to the best French 

 buhr, have been quarried. In the southwestern corner of Aiken county, on 

 Hollow creek (E. D. 16), beds of lignite .occur, underlaid by clay that was 

 used by the ordinance department during the late war for the manufac- 

 ture of fire-proof crucibles, and pronounced equal to the best Stourbridge 

 clay for that purpose. Similar beds of lignite are found in Chesterfield 

 county, on Whortleberry branch, and at Mr. Croghan, underlaid by clay of 

 the same character. 



4th. Beds of a white siliceous rock, varying from a laminated siliceous 

 clay to a hard rock, having a jointed structure, breaking with a conchoidal 

 fracture, and resembling menilite. This curious rock has been traced from 

 near Aiken C. H. to the northern f)art of Clarendon county. In the latter 

 county there is a remarkable occurrence of it on the public road just 

 north of Gov. Manning's residence (3d Sup. Dist. E. D. 15). On the head 

 waters of Congaree creek this rock is sawed into blocks, fashioned with 

 an axe, and used for building chimneys. It resists disintegration Avell, 

 and its extreme lightness facilitates its carriage and handling. 



Below the series of strata thus described are the great beds of loose 

 sand, intermingled with kaolin and variousl}' colored clays, which rise 

 into the extensive sand hill region, lying north of the red hills. 



SOILS. 



The reddish loam of this region presents an appearance somewhat sim- 

 ilar to that of the soils derived from the hornblende rocks in the upper 

 country, but it is not so tenacious and waxy. Although when not culti- 

 vated it becomes very hard in dry weather, in wet weather, owing to the 

 large amount of sand it contains, the intervals when it can not be worked 

 are short. Vegetable matter rots rapidly in it, and for this reason long 

 manures (as composts) are better adapted to it than commercial fertilizers. 

 The former are rapidly incorporated and well retained, and there is no 

 soil that responds so well or is so capable of great improvement under 

 treatment with stable and lot manures as these. Worked without ma- 

 nure they rapidly consume themselves and become unproductive. 



