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chemical properties sufficiently testify its bituminous nature. It 

 appears to have been formed from vast deposits of wood, which 

 have been so circumstanced, as to have undergone the bituminous 

 fermentation to a certain degree ; but have not suffered a change 

 sufficient to reduce it to a fluid bitumen. That a portion of it has 

 undergone, even this change, may justly be inferred, from the actual 

 presence of bitumen in different parts of the mass ; as well as from 

 the bituminous impregnation of the roof, which impregnation was 

 most likely to have proceeded from the absorption of the fluid bi- 

 tumen, much of which, from its levity, would rise to the upper part 

 of the closely pressed mass of bituminous wood. The flat shivery 

 state of that which is termed the knotty-coal, as well as of that which 

 is termed the board-coal, seems to point out, that, after the bitumini- 

 zation had proceeded to a certain point, this substance had been 

 deprived of its moisture : the state in which it is found being 

 exactly that, in which Avood, having suffered such a degree of bitu- 

 minization, might be expected to be found, after having been per- 

 mitted to become dry. Nor is it an objection of any force that it 

 is now found in a moist state ; since, supposing its exsiccation to 

 have been once complete, and the fermentative operation quite 

 stopped, no subsequent addition of moisture could be expected to 

 renew the fermentation, or to soften it so as to render it capable of 

 uniting in a close mass. 



Yours, &c. 



