on the Geological Survey of South Carolina. 73 



" 7th. That the submerged stumps of trees, found below the 

 level of high tide along the coast, are not the result of subsi- 

 dence, properly so called, but must be referred to the encroach- 

 ment of the sea upon the land, and to the peculiar character of 

 the deposits in which they grew. 



" That the almost entire absence of fluviatile shells in the 

 recent and tertiary deposits, is mainly due to two facts : 1. That 

 there is a considerable space between the line of brackish and 

 salt water, where neither fluviatile nor marine forms can exist. 

 2. That the streams have not transporting power sufficient to 

 bring down fresh water shells. So long as these circumstances 

 exist there can be no mixture of fluviatile and marine shells." 



Practical Geology. — With the tertiary, of course, the portion 

 of the work devoted to descriptive geology ends. The remain- 

 der of the volume, excepting the appendix, is devoted to practical 

 or economical geology. Under this head we have presented by 

 the author an interesting and valuable treatise upon soils in gen- 

 eral, their classification, physical properties and chemical compo- 

 sition : — Upon the composition of cultivated plants : — manures, 

 animal, vegetable and mineral, with their effects: — rotation of 

 crops and draining: — lime burning: — metallurgy: — the manu- 



facture of iron : — the extraction of gold from its ores: — and upon 

 the materials used in the arts found in the state, &c. &c. The 

 greater portion of this we pass over without particular comment; 

 not that it is of less interest than other portions of the work, 

 but because it relates to matters not exclusively concerning the 

 geology of South Carolina. We will touch, however, upon one 

 or two points. 



Of the extraction of gold from its ores, Mr. Tuomey gives a 

 detailed account, hoping thereby to call the attention of inventors 

 of machinery to the very rude processes by which it is effected, 

 in order that some improvement may be made in the machinery 

 used. He therefore particularly describes all the means adopted 

 at the mines for the separation of the metal, and gives figures of 

 all the various machines used in the state for the purpose. We 

 mention this tact, because our article may meet the eye of some 

 reader, who will learn by it what is required, only to supply the 

 want. 



Of the metallic substances found in the state, besides gold and 

 the oxyds of iron, of which notices have been taken, the fol- 

 lowing are enumerated : manganese, lead, copper, bismuth, gra- 

 phite, oxyd of titanium, sulphuret of iron. 



A number of mineral springs are mentioned as occurring in the 

 upper districts, some of which are visited for their medical virtues. 



Appendix.— \n the Appendix, a catalogue of the fauna of South 

 ^arolma is given, prepared by Dr. Lewis R. Gibbes of the South 

 Carolina College. 



Second Series, Vol. VIII, No. 22.— July, 1849. 10 



