300 
If this should be even imagined as possible, in the instance of a 
single line— can it be admitted that such a regular abstraction and 
supply, imitating exactly those processes only known to be per- 
formed by organized parts, could thus take place, through every 
series of the vessels, and every fibre of the decayed wood ; and 
thereby produce an appearance, not in the least differing from that 
of the original wood itself. But were even this to be claimed as 
possible, and were it allowed that the form of the wood might be 
thus preserved, and its structure imitated ; how should we, on this 
Iiypolhesis, account for the original colour of the wood being exactly 
retained Can it be supposed that the original molecules being thus 
removed, that the added particles of earth, derived from the sur- 
rounding mingled mass, should be so disposed, that the arrangement, 
and blending, of the variously coloured particles should yield an 
exact imitation of all the different hues, and of the disposition of 
the characteristic shades of colour, of the original wood. It indeed 
appears to be impossible, that the almost fortuitous disposition of 
the atoms, by which such a substance would be formed, could per- 
fect so exact a resemblance in the figure, structure, and colour of an 
organized body, that the eye, unaided by the touch, should not be 
able to discover the difference. 
The theory of Dr. Hutton next demands examination. The im- 
pregnation of silicious fossil wood, he supposes to have been effected 
by injection with flint, in a state of simple fusion by fire. ‘‘ With 
whatever different substances,” he says, “ the woody body shall be 
supposed to have been penetrated, in a state of solution by water, 
the regular structure of the plant would still have remained, with its 
vacuities, variously filled with the petrifying substances, separated 
from the aqueous menstruum, and deposited in the vascular structure 
of the wood. There cannot be a doubt with regard to this proposi- 
tion ; for, as it is, we frequently find parts of the consolidated wood, 
with the vascular structure, perfectly in its natural state and situa- 
