aOTPiiN- STONE. 49 
<ira'm«d Uirougli the loose materials, which fill the hollows and 
fissures of the rotten-stone tract. 
7. In this mineral dejiot are found, with the rotten-stone, 
fragments of chert ; fn'gments of a calcareous stone in every 
possible state, intermediate between rotten-stone and perfect 
limestone} rotlen-sione uitli nuclei of solid Hack limeslotie ; 
t^c. tife. 
8. The calcareous stone, which forms, in these instances, the 
central parts of the nodular lumps of Koi ten-stone, has the 
ex/itrnH/ characters of the black limestone or marble, found at 
Ashford-in-the-waters, &c. but ditiers, somewhat, in its inier- 
nal properties, from any stratum of limestone yet discovered in 
Derbyshire. 
9. Marine reliquia are sometimes found in the hard Rotten- 
stone ; and these are generally such as haie been observed to be 
most frequent in the black marble viz. EnlomoUtiius Der- 
liensis Conchyliolillius Breynii, &cc. (v. Pet. Deib. t . 4 o, 39, 
&c) 
Such are the principal phenomena, which were noted during Dodurtion 
my examination of the depot of Rotten-stone near Bakewcll. 
— The conclusions, to which this examination led, have been <lnce<lfroin a 
already alluded to ; namely, that RoHen-slotic is produced ly 
the disintegration of a particular variety of' limestone, proLally 
. a Hack marhk i and that, consequently, authors are incorrect in 
• considering the original substance of this fossil to have been an 
I argillaceous stone. 
Irwill here, however, be asked — how is the prorluction of 
I this particular substance from another, chemically as well as 
externally distinct, to be accounted for ? and, if Rotten-stone 
be actually the result of a certain change in black marble or 
limestone, why is it not found in every situation, where such 
I roi'k occurs ? To answer these questions satisfactory will 
I perhaps be impossible to answer them, however, in any 
way, without having recourse to the reciprocal transmutation of 
what have hitherto been considered, as simple, eletnentary parts 
In 
Vei.. XXXVI.—No, 165. 
£ 
