330 
I Jiave obtained other specimens of this fossil wood, in which the 
loose and shivery texture of rotten -wood is still more decidedly 
manifest. This kind of fossil wood appears to be that to which the 
term of silicious wood may be most appropriately applied. The 
second kind of silicious fossil wood is that which, previous to its 
impregnation with silex, had undergone the change which the bitumi- 
nous fermentation induces ; this kind of fossil wood may be termed 
siLicizED BITUMINOUS WOOD ; and its several species will be found 
to have depended much, for their general appearance, on the degree 
to which the bituminizating process had proceeded, in the wood, 
previous to its lapidefaction. 
Bituminous wood, we have seen, may exist in two states j in one, 
the fibres, although rendered bituminous, and perhaps softer than 
in their original state, have not been so far changed as to run to- 
gether, and destroy the natural separation which exists between them. 
A specimen of bituminous wood in this state, dug up at Blackwall, 
is represented at Plate I. Fig. 1. In the other state, the bituminous 
fermentation appears to have proceeded so far, as to have occasioned 
such an approach to fluidity, in the bituminized wood, as to have 
allowed it to run together in a mass, by which the ligneous texture 
and fibrous appearance have been lost. The Bovey-coal, of which 
we have already spoken, and which has been figured in Plate I. 
Fig. 3. is an example of bituminous wood, which has existed in this 
state. In specimens of this wood, its state of softness, nearly ap- 
proaching to fluidity, may be inferred from the fibres, in one part 
of a specimen, being disposed in various distorted directions, very 
different from those which naturally belong to the woody fibre, 
whilst, in another part, they seem to have run together in one mass 
in which every trace of fibrous texture is obliterated. 
SILICIZED BITUMINOUS WOOD may, therefore, agreeable to these 
two diflcrent states, in which bituminous w^ood has existed be 
divided into those, in which the bituminized fibres, having retained 
