46 Phosphate Rocks of South Carolina, 
erties extending through several years. Whereas the 
cooked or manipulated rock, (the Superphosphate, 
fertilizer,) is nearly exhausted the first crop, its action 
is immediate. 
There is little doubt that an application of the raw- 
ground-phosphate, to the poor and almost worn out 
lands everywhere to be met with, still under cultiva- 
tion, will be to a great extent beneficial, as none of 
these lands contain a particle of lime in any form, and 
possibly the native acid in the soil will gradually cook 
a sufficient quantity annually to aid and support the 
crop; or, in other words, gradually convert, in Na- 
ture’s laboratory, the raw Phosphate into the Super- 
phosphate of commerce. 
And of this, our Marl experiments in 1844 prove 
in a measure the reasonableness of the inference. 
The upper layers of the Marl of the Ashley, applied 
to cotton and corn, produced greater effects than Marl 
obtained from the depth of ten or twelve feet below; and 
we can only account for this difference from the fact 
afterwards ascertained, (but not at the time even sus- 
pected,) that the upper layers contained more Phos- 
phate of Lime than the lower, the “ drippings” of the 
Phosphate Basins above having been 7wzdided by the 
top layers of Marl underlying them. Hence as it was 
a raw, uncooked Phosphate of Lime, similar (and, as 
we confidently believe, even greater,) results must 
attend the application of the ground Phosphates, 
which contain from fifty to sixty per cent. of Phos- 
phate of Lime. 
