339 







been deposited, whilst in a fluid state, and afterwards congealed. 

 There appears, he says, commonly, in this wood, something which 

 resembles amber, or resin; and which has, by some, been actually 

 supposed to be so, and to have assumed a stony hardness. This 

 he, however, concludes is not the case ; but believes that this sub- 

 stance, as he had already asserted, must actually be a particular 

 species of spar*. 



Nothing certainly, as far as the evidence of the eye can be ad- 

 mitted, can more strongly favour the opinion, that the formation 

 of this species of fossil wood has depended on a combination of 

 silicious and bituminous matter, than the peculiar lustre which 

 it possesses ; which is precisely such as might be expected from 

 the mixture of these two substances. Different specimens, indeed, 

 seem to display the bituminous Wood in all its several degrees of 

 change ; from its first assumption of a bituminous nature, to the ac- 

 quiring of the state of pure translucid bitumen; and evince its hav- 

 ing obtained, in these several states, its present degree of hardness, 

 from the introduction of the silicious matter. In such varieties of 

 this fossil wood, as manifest evident and strong traces of the original 

 fibres, there seems to be reason for supposing, that the wood had 

 not undergone the bituminizating operation, to such a degree as to 

 have been thereby rendered a fluid bitumen. But that the wood, 

 previous to its impregnation with silicious matter, had been so far 

 affected by its bituminization, as to have been rendered soft and 

 yielding, is evident from the appearances which specimens of this 

 kind of fossil wood generally yield. Their fibres will generally be 

 seen disturbed, and thrown out of their natural direction ; not as if 

 broken, but as if displaced whilst in a yielding state, and thrown 

 into gentle contortions and undulations. An idea of what is here 

 meant may be furnished by a view of PI. II. Fig. 7. 



* Recueil des Monumens dcs Catastrophes, &c. torn. iii. p. 32 and 39. 



