232 GEOLOGICAL SURVEY 
originated among an agricultural people. The burning of the remains of the crops, is sometimes 
practiced, under the impression that the ashes which are left are the only valuable part, or that the 
ashes are the product of the combustion, and would not result from ordinary decomposition. 
After what has been said on the value of the organic parts of soils and manures, the error of such 
an impression must be evident. In the greater number of the soils of the State, organic matter is 
quite as deficient as any of the other elements. 
There are, in the State, various sources of mixed manures that are extremely valuable; every 
where along the coast, there are, at the mouths of thegrivers, immense salt marshes, rich in nearly 
all the inorganic parts of crops. 
The following is an analysis, by Professor Shepard,’ of charred salt-marsh,* from the coast of 
Georgia. 
Water ofpabsorption:= ssa sec ane Seine 6.000 
Carbon and inorganic matter-.--.----..---- 11.000 
Nilica 2] == sees eee eee een 65.000 
Alumina =s22sssnssss-eneses== oon e se 6.000 
Protoxidelofarons==-soeeve——sS=-255—= == 5.500 
Carbonate of lime and magnesia 
Chloride of sodium, 
Chloride of calcium, 
Sulphate of lime, 
Sulphate of magnesia, 5.839 
Sulphate of potassa, 
Sulphate of alumina, 
Carbonate of potassa. 
100-000 
In the immediate vicinity of the marshes, this substance is applied,to cotton, without charring or 
any other preparation. The charring, at least, diminishes the weight, and it might be profitably 
transported some distance up the rivers. It would be a capital addition to a manure heap for the 
purpose of fixing the volatile products of decomposition. , 
The black vegetable mud, so abundant in the swamps of the State, is also a valuable manure, 
when properly treated. It may not, however, be applied in the green state, like marsh mud. I 
have already explained the effects of the partial decomposition of vegetable matter under water. 
Swamp mud must be exposed to the influence of the atmosphere, or mixed with marl or stable 
manure, before it is applied to the soil. It is also a valuable addition to farm-yard manure, for pre~ 
venting the escape of amonia, and for absorbing liquid matters, 
Or MiInerAL Manures. 
To this class belong gypsum, lime, marl, &c. In treating of these I shall confine myself, prin- 
cipally, to those found in the State. 
Gypsum is a sulphate of lime, and is generally applied to artificial meadows, and to clover, as a 
top-dressing ; on the latter, it appears to have a specific effect. 
There appears to be great diversity of opinion on the subject of the application, effects, and 
* The term “salt-marsh” is applied on the coast to the mud and other matters of which the marshes are composed. 
