[ 1 9 ° ] 
dently prove the action of the fire even on this higher 
or upper ftratum ; and its interior parts likewife prove 
as evidently, that this fubffance has been formerly 
petrified wood, but from which the ligneous parts 
have been driven away, and confumed by a heat fu- 
perior to their refinance. 
I do not doubt, but had my time permitted me to 
make further refearches, I fhould have found in the 
mountain pieces of petrified wood not yet altered or 
deflroyed by the adtion of the fire ; but my leifure 
not anfwering to my wifhes, I thought I might remain 
contented with what I have now the honour to pre- 
fent to the Society, and which feems to me fufficient 
to determine the procefs of nature in the generation 
or production of Tripoli. 
If I am afked how all this vaft quantity of wood 
could be heaped or gathered together in this moun- 
tain ? I anfwer, i°. That it is not to be luppofed 
that the feveral layers or ftrata of Tripoli, perfedt or 
imperfedt, follow each other without any interrup- 
tion. 2dly, It may be allowed me to fuppofe a de- 
luge, whatever it was, and which has covered many 
parts of our globe, to accumulate here all this wood, 
and even aid its petrification, ^dly, A further proof 
of my affertion is the wood-coals which incontefl- 
ably are found deep in the earth ; for there are intire 
quarries of them in Saxony, in the neighbourhood of 
Halle, and which do not fuppofe a lefs quantity of 
wood : belides, it is ufelcfs to difpute again!! obfer- 
vation and experience, when they are folidly efla- 
blifhed. 
* Wood-coals. The author ufes the words “ charbons de bois 
but what he means by his intire quarries of charbons de bois, I de- 
clare myfelf ignorant of. 
I muft 
