334 
AGRICULTURAL GEOLOGY.— NO. 5. 
We noted several other things at Mr. Bucka- 
lew's, which we intended to speak of at this 
time, but our article is already so long we must 
forbear for the present. We shall, however, 
again recur to them. In the meanwhile, if any 
one wants to make the acquaintance of an in- 
telligent, energetic man, and see good cultiva- 
tion, such as any farmer can practise, if he 
pleases, however limited his means, let him 
make a visit to Mr. James Buckalew, of New 
Jersey. 
•-#-. 
AGRICULTURAL GEOLOGY.— No. 5. 
The soils which overlie clay-slate rocks vary 
much in composition. In many instances, they 
are drift soils ; that is, they have been trans- 
ported from a distance and deposited upon a 
clean surface of rock. Thus, in the middle 
western counties of this state, gravelly and gyp- 
seous clays lie upon the slate rock, which latter 
influences very slightly the character of the im- 
posed soil. If these rocks, which may be looked 
upon in the mass, as a sort of salt-water-mud 
rock, vary much in their own chemical compo- 
sition ; any soil formed of them must also vary 
in composition. For instance, between beds of 
shale, a bed of good limestone' is occasionally 
met with; in other localities, the new bed is a 
flag or sandstone, both of which alter the com- 
position of the soil, the former enriching, the 
latter impoverishing it. Where trap rock or 
greenstone is pushed up through slate, the soil 
is much benefitted by the increase of lime and 
alkali, which it thus receives. Such is the con- 
dition of much of the soil of Canada, border- 
ing Lake Superior. The palisades, along the 
Hudson River, are trap rocks, but have not the 
same influence on the subjacent soil as in many 
other places. 
The soil which is formed by the decomposi- 
tion of a slate rock is a stiff clay ; and all 
clays which are not of drift origin are derived 
from the wearing away of slate. We have al- 
ready asserted clay slate to be a marine mud, 
derived from the decomposition of a previous- 
ly existing rock. This previous rock contain- 
ed the mineral felspar, the decomposition of 
which produces stiff clay. The mineral chlo- 
rite, also, produces tenacious clays by decom- 
position, and both felspar and chlorite, existing 
in most true slates, form the grand basis for 
a clay soil. Felspar contains in 100 parts, 65 
of silica, 18 of alumina, and 17 of potash, and 
these are united together as a silicate of alum- 
ina and a silicate of potash. The mineral chlo- 
rite, that which tinges slates of a green color, 
is not so prevalent a constituent of slate as fel- 
spar, and contains in 100 parts, 26 of silica, 21 
of alumina, 26 of magnesia and 14 of oxide of 
iron. The agreement of these two minerals is 
in the possession of silica and alumina, and any 
soil formed from them must contain these two 
substances in excess. 
The felspar being worn to a fine powder and 
deposited in water, has had its potash almost all 
washed out, and much of the magnesia of the 
chlorite has been removed by a similar process. 
But a slate rock is not wholly made up of the 
debris of these minerals ; deposited in sea water, 
where weeds and wreck grow, it contains im- 
bedded in its layers an amount of marine fuci, 
and terrestrial flowerless plants, sufficient to 
give the rock a dark tint, and in a few cases to 
render it so bituminous as to burn continuously 
when once inflamed. Such is the condition of 
the Genesee black slate, and the fossiliferous 
shales of the central and western counties of 
this state (Ontario, Seneca, Tompkins, Steuben, 
Cayuga, &c.) Such rocks also contain the sa- 
line matter of the ocean of that period, in the 
form of common salt, gypsum, and cloride of 
magnesia, in minute proportions. A few of the 
beds of shale in the great wheat district of New 
York contain as much as 6 per cent, of this sa- 
line matter, a proportion nearly equal to 20 tons 
per acre. An ordinary shaly-slate rock is ca- 
pable of yielding an average, in 100 parts, of 
Silicates of alumina , iron, and mag- 
nesia, 92.97 
Soluble saline matter, 6.00 
Vegetable matter, 1.03 
100.00 
Very many of the shales contain as much as 4 
per cent, of lime in the state of carbonate (mild 
lime). The soil would be rich, indeed, which 
would be found to contain as much soluble mat- 
ters as exist in the foregoing shale ; such never 
occurs. In the weathering of the rock, the 
rains and stream water wash out the greater 
portion, but never leave so much as 2 per cent, 
behind. 
The greater portion of Dutchess, Ulster and 
Putnam counties have a stiff clayey soil, aris- 
ing from the decomposition of slate rocks. The 
following are the compositions of two soils in 
Ulster county : — 1. 2. 
Water of absorption, 1.00 2.56 
Vegetable matter, 3.04 5.53 
Silica and silicate of alumina, 88.08 88.36 
Alumina and oxide of iron, 4.04 1.61 
Lime, 0.03 0.78 
Magnesia, 0.02 0.14 
Soluble salts, as common salt, 
plaster and potash, and 
phosphoric acid, 2.02 1.02 
100.00 100.00 
No. 3 is a stiff clay from Westchester, and 
No. 4 is a clay from Seneca county, the compo- 
sition of which is as follows : — 3. 4. 
Water of absorption, 4.00 4.00 
Vegetable matter, 4.06 4.23 
Silicate of alumina, 85.08 87.00 
Alumina and peroxide of iron, 4.08 4.40 
Lime, 0.05 0.01 
Magnesia, 1.04 0.01 
Soluble salts of potash, with 
common salt, plaster, and 
phosphoric acid, 1.08 1.01 
102.00 101.00 
These analyses shew the general characters 
of clayey soils. Leaving out of view these sub- 
stances which are in some degree the result of 
