[ * I* ] 
the reft, and prefcrve them from a more immediate 
Decay, by cutting off their Communication with the 
exterior Air. Rains, in Proccfs of Time, muft have 
wafhed off from the adjacent Hills to l'ome certain 
Diftance, and depofired in the neighbouring Val- 
ley, but mixt with other heterogeneous Subftances, 
as decayed Wood, Earth, a Quantity of chalky 
Particles, fufRcient to involve, by a continual Ad- 
dition of new Lamina , Roots, Trunks, Branches, 
Twigs, and the broken Extremities of Twigs; and 
tending continually to formMafles rcfembling the fup- 
pofcd Particulars. I don’t now imagine, tho’I once 
•thought fo, that thefe chalky Particles have penetrated 
the Wood itfelf, and converted it into its own Sub- 
ftancc, in the Nature of ordinary Petrification, except 
herc-and-there fome few particular Pieces; but I rather 
fuppofe, that the Pieces of Wood have been in veiled 
continually by additional Lamina \ thar the fir ft La- 
mina muft have adapted itfelf to, and aftumed the ex- 
terior Shape, whether finooth or knotty, of the in- 
clofed Wood ; that the others have proceeded accord- 
ingly ; that the Extremities have gradually rounded 
themfelves; and that in the Interim, till they were 
wholly clofed, the included Wood has been infenfi- 
bly attenuated by the palling Moifture, and, Particle 
by Particle, either intirely, or in Part only, walled 
away. And, though it may be objefted againll this 
Suppofition, that fome Pieces are intirely folid, as 
one of thofe two large Pieces is which you have by 
you, and has the Refemblance of White-thorn ; yet 
thefe are but rarely found, and may very well be fup- 
pofed to have been a Species of Wood of a more 
folid and durable Contexture; which might confe- 
5 quently 
