196 
in the foffil creation; and, pleafed with 
the idea, proceeded to form a regular 
theory of minéral vegetation. A more 
extenfive acquaintance with this branch 
of natural’hiftory, has, however, fhown 
the theory, like too many others, to be 
unfupported by facts; and deprived it of 
the principal evidence in its favour, by 
difcovering coral to be of animal origin; 
end that the various bodies, formerly 
called figured foffils, owe their form to 
the remains of animals and vegetables, 
buried in the earth in different circum- 
ftances, or to chemical principles. But 
though the configuration of extraneous 
and cryftalized foffils may be thus ac- 
counted for, there are many others, of a 
different nature, which evidently bear 
2 generally regular fhape; and the idea 
of organization and growth being given 
up, their prefent Agure muft refult from 
their original formation. Common peb- 
bles, it is well known, are ufually of a 
roundifh fhape, though in fome parts of 
the coantry much more fo than in others: 
in many places, it is difficult to find one 
which has not this form, anda tolerable 
fmooth furface; yet many, even of thofe 
which have the {mootheft furface, have 
evidently been formed from fragments of 
regular ftrata, and had they been of their 
prefent degree of hardnefs, when broken 
off, muft have required a very long 
period, or a great degree of attrition, to 
wear away their afperities, and bring 
them to their prefent fate. It is highly 
probable, therefore, that they were once 
iufficiently foft, to be eafily brought, by 
the motion of water, into their prefent 
form; an operation, which fragments of 
different {pecies of ftone are conftantly 
undergoing on all {ea-coafts, and that, as 
the facility of removal increafed, by their 
original ruggednefs wearing down, they 
have been gradually carried away to 
deeper parts of the fea; till fettling in 
_fome place, where the effect of the agita- 
tion of the {urface wasinfufiicient to carry 
them farther, they have accumulated, in 
time, to a bed of confiderable extent. 
This account of the formation of pebbles, 
- and perhaps of fome other {pecies of 
foffils, is confirmed by fome of them con- 
taining imprefiions of fhells, and by the 
firn€iure of others, which are compofed 
ef concentric crufs, including a nucleus 
ef a different colour, and frequently of 
much greater hardnets, than the outer 
part ; and by fuch as are of this ftructure 
berg feldom found among thofe that are 
formed of a more homogenous {ubftance. 
In the ifle of Sheppey, near Minfter, the 
On the Fi drmation of Pebbles: 
cliffs are about 100 feet in height, and 
are compofed of clay and blue’ marle,” . 
pieces of which fallmg frequently on the 
fhore, are worn {mooth and rounded by 
the motion of the fea, and after lying 
there for fome time, harden, and become 
the pyrites or copperas ftones, which are 
gathered by the poor of the ifland, every 
{pring, for the vitriol works. That this 
is the true origin of the pyrites, cannot 
be doubted ; as pieces of marle may be eb- 
ferved on the fhore, in all the different 
degrees of hardnefs, thape, gc. from the 
rough ftate in-which they fall from the 
_cliffs, till they become complete pyrites; 
and as there are trees and bufhes grow- 
ing above, it is not at all furprifimg that 
thefe fragments of marle, rolled into 
form on the fhore, frequently mclofe a 
piece of wood. f have even found fome 
hazel nuts fo thoroughly impregnated 
with vitriolic particles, that they appear- 
ed converted into perfeé pyrites, but fill 
retaining the exact form and lineaments 
of a nut. The‘e inftances fhow the ef- 
feét of the motion of the fea, in a very 
fhort period, which, if long continued, is, 
doubtlefs; capable of producing fimilar 
effects on much harder fubftances; and 
when it is recolleéted, that this power 
has been conflantly operating for fo many 
ages, on the moft extenfive icale, it may 
not appear infufficient to account for the 
formation of the immenfe number of peb-— 
bles feattered over the’ earth. 
April 4, 1796. Lie G, 

To the Editor of the Monthly Magazine. 
STR, 
At a time of fo great fcarcity, every 
hint which may have a tendency to 
encreafe the food of the labouring poor, 
muft be acceptable; and as feveral per- 
fons have, in the public papers, recom- 
mended the cultivation of Indian wheat, 
the foliowing is a praétical account of its 
‘cultivation in England: The land thould 
be a loamy fand, very rich. In the be- 
ginning of April, the grains fhould be fet 
like hops, at two fect difance, fix or eight 
grains in a hill, each grain about an inch 
deep in the ground. The feed from New 
England is the beft. In the beginning 
of, May, the alleys fhould’ be hoed, 
and the hills weeded and earthed up 
higher. At the latter end of that month, 
all the fuperfluous ftalks fhould be taken 
away, and only three ftems of corn left in 
each hill. By the middle of June it wall 
cover the alley. It grows much like 
bulrufhes, the lower leaves being like 
broad flags, three or four inches wide and 
/ as 
| [April 
