IlOTTEN STONE. 
47 
nic and sometimes, perhaps, of genuine volcanic origin ; he 
adds, however, that “ it also frequently arises from the decom- 
position or disintegration of other stones.’* The latter ob'Cr- 
vation appears to apply strictly to our Derbyshire rotien ilont*, 
which is usually considered by mineralogists as a variety of 
Tripoli, originating from some unknown decomposed stone of 
the argillaceous kind. That the substance producing rotten 
stone is, however, in its primary state, a rnicarions and not an 
ar^i//ateo«y stone, can only be doubted, I think, by iho<-e who 
have not had an opportunity of examing this fossil in its native 
repository. Indeed, I feel little hesitation in affiiming, that 
the phenomena, attendant on the substance in question, 
strongly support the original idea of the late ingenious Mr. 
Whitehurst, who from personal and cxtctisive observation, was 
led to conclude, that the parent rock of the Derbyshire rotten 
stone was ;/u:r//ej-, or some other variety ot our dark- 
coloured iime-slones. 
It is some years back since I availed mvself of a favourable Account of 
. . ■ . the rotu II 
opportunity that occurred of exainimng the rotten-stone pits Mone juts on 
on Bakewell MoorJ, and wliich, 1 undeistand, are only ojvened 
I at particular periods — that is, every third or fourth year, ac- 
I cording to the demand which may then prevail for the fossil 
I as an article of traffic. On looking over the memoranda, made 
at the time of visiting these pits, I find they difl'er, in some 
trifling respects, from Mr. Whitehurst’s account of the mode 
in which rotten stone is procured, the appearances it exhibits as 
a mineral deposit, &c. ; and as no late author that I am ac- 
quainted with, has entered into any detail on these subjects, 
• Cariosus /inplorum. Gmcl. Linn. Syst. Nat. p. H6. — Tripoli. Kir- 
vran. El. .Miner, p. S02. 
t Vide Whitehurst s “ Inquiry into the original state and formation 
t of the Earth.” 
t Rotten stone also occurs at Wardlovv Mire, and, as I am in- 
formed, at A^hford, and some other paits of the county ■, but I uni not 
acquainted with the local circcmstauccs with which it is attended in 
those places. 
the 
