This appears from the wood being penetrated
partially, some parts not being penetrated at all.
Now, in the limits between those two parts, we have the most convincing
proofs, that it had been flint in a simple fluid state which had
penetrated the wood, and not in a state of solution.
_First_, Because, however little of the wood is left unpenetrated, the
division is always distinct between the injected part and that which is
not penetrated by the fluid flint. In this case, the flinty matter has
proceeded a certain length, which is marked, and no farther; and, beyond
this boundary, there is no partial impregnation, nor a gradation of the
flintifying operation, as must have been the case if siliceous matter
had been deposited from a solution. 2_dly_, The termination of the
flinty impregnation has assumed such a form, precisely, as would
naturally happen from a fluid flint penetrating that body.
In other specimens of this mineralising operation, fossil wood,
penetrated, more or less, with ferruginous and calcareous substances,
has been afterwards penetrated with a flinty substance.
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