48 THE LOWKR PINK BELT, OR SAVANNA REGION. 



in a few instances perhaps by tlie action of storms, is sufficient to account 

 for any movements that these water-worn nodules have undergone. The 

 rock of commerce occurs always above the marl, and is known as the land 

 or water rock, according as it is found in the one element or the other. 

 The water rock is darker in color and harder than the land rock, and is 

 frequently found in a layer or sheet of cemented or tightly compacted 

 nodules, overlying the marl at the bottom of the rivers and creeks, where 

 it either forms the bottom itself or is overlaid by a deposit of mud of 

 greater or less depth. It has been seldom dredged for at a depth exceed- 

 ing 20 feet. The land rock is found at a depth of 2 feet to 10 feet (and 

 more under elevations) below the surface of the soil, but is not mined at a 

 depth exceeding 5 to 7 feet. It is found' in masses or nodules, varying 

 from the size of a potato to several feet in diameter. These nodules are 

 rounded, rough, indented, and frequently perforated with irregular cav- 

 ities. They vary in color from olive or bluish black to a yellowish or 

 grayi.sh white. Their specific gravity is 2.2 to 2.5. Their hardness from 

 0.5 to 4." The fragments of a nodule give pff a peculiar foetid odor on 

 friction. By analysis it is found to contain phospliate of lime 55 to 61 

 per cent., carbonate of lime 5 to 10 and organic matter and water 2 to 

 10 per cent., "with small quantities of fluorine, iron, magnesia, alumina 

 and sulphuric acid, besides sand. The land rock is found in a loose 

 layer, varying from a few inches to 30 in depth, averaging about 8 

 inches. It occurs in sand, mud, cla}^ or peat, and is often intermingled 

 with numerous remains of land and marine animals. Among the former 

 are the remains of the mastodon, elephant, tapir, deer, and of our do- 

 mestic animals, the horse, the cow and the hog. Thus showing that these 

 very animals whicli were imported by the first white settlers had once 

 iuhaljited this region, from which they had disappeared, so far as tradi- 

 tion informs us, before the advent of man, furnishing Prof. Agassiz with 

 one of his strongest arguments in favor of '' independent centres of crea- 

 tion." The remains of these land animals are found intermingled with, 

 but never imbedded in, the phosphate rocks, giving no evidence that there 

 was any community of origin between them. So abundant are the re- 

 mains of marine animals that Mr. Toumey named this formation the 

 " Ashley Fish Bed." Most striking among these remains are the beauti- 

 fully preserved t^eth of sharks, from 2 inches to 4 inches in length ; if the 

 proportions between the teeth and the bodt found among existing sharks 

 obtained Avith these monsters, they must have been (]0 feet to 80 feet in 

 length. The sharks teeth, on the other hand, found in the Santee marls 

 do not differ nuich as regards si^e from tho.se of the sharks now living on 

 the coast, and artesian wells in the phosphate region yield, at a depth of 

 700 feet below, these colossal teeth — teeth similar in size to the ancient 



