D. A. Wells on the Soils of the Scioto Valley. 15 
would state, that one of the best tobacco soils upon the Island of 
Cuba, some time since examined by Dr. A. A. Hayes of Boston, 
was found to contain ninety per cent. of the peroxyd of iron. 
And yet this soil, which we might suppose would be barren, 
without the usual proportions of siliceous and aluminous matter, 
is, on account of its great fineness, and the remaining ten per 
cent. of organic and inorganic constituents, enabled to produce 
the best crops upon the island. 
These advantages of fineness, it is evident the Ohio soils will 
always possess, as it cannot be exhausted by any system of agri- 
culture. ‘To this point I wish to call especial attention, since if 
due regard be paid to the supplying of these soils with the neces- 
sary quantities of organic and inorganic nutriment, they must 
and always will be unrivalled for fertility. An examination of 
the silicious insoluble constituents of these soils, leads to the be- 
lief, that they have not been derived from the disintegration, or 
ecay of any underlying or contiguous rocks, but from materials 
brought from a distance. The rocks of Ohio are for the most 
part carbonate of lime, and yet in only one of the soils examined, 
a subsoil, could the slightest trace of carbonic acid be detected. 
e method adopted for testing, was by placing the soil in a 
favorable light upon a watch-glass, covering with dilute warm 
acid, and noticing carefully for the appearance of effervescence. 
In this way the most minute quantity of carbonic acid could not 
fail of being detected. In the examination of the soils of Mas- 
sachusetts by Pres. Hitchcock, the same remarkable deficiency of 
carbonates, even in soils resting upon carbonate of lime rocks, 
Was noticed. The same conclusions have, I understand, been 
arrived at by Dr. D. D. Owen, from an examination of the soils 
of Iowa and Wisconsin. From these facts we believe that the 
alkaline and earthy carbonates are to a much greater extent want- 
ing in arable soils than is generally supposed. This supposition, 
however, should perhaps be confined to the northern portions o 
this country, which have soils resulting mainly from materials 
distributed by the drift agency. paewag 2 < 
Yhen a soil containing considerable quantities of organic mat- 
ter is tested for carbonates after ignition, they will generally be 
found, the crenates and apocrenates passing over into carbonates, 
and remaining fixed except at a high temperature. : 
microscopic examination of the siliceous insoluble residues 
inorganic substances, showed that they are composed of the de- 
tritus of syenitic and porphyritic rocks, consisting of minute par- 
ticles of quartz, feldspar and yellow jasper without the presence 
of mica. I would not, however, present these facts as wholly 
conclusive respecting the origin of these soils; the quartz, jasper 
and feldspar may haye had their immediate origin in the Waverly 
