318 Cursory Remarks on 
the production of 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 rock 
occurs? 'To answer these questions satisfac- 
torily will 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, 
elementary parts in mineral compositions,* 
we must first recur, it is evident, to the nature 
of the constituent matter of the original rock, 
as well as of the substance, which the disin- 
tegration of such rock has been presumed to 
produce. 
Limestones, it is well known, are composed 
principally of an indurated calcareous carbo- 
nate ;—Rottenstone, according to the following 
analyses, of alumine in a loose or earthy form, 
and with its constituent particles in a very 
minute state of division—But we must remem- 
* The transmutation of silex into lime, or that of lime 
into silex or alumine, however strongly contended fur by 
some modern Geologists, most assuredly ought not to be 
assumed in apy attempt to account for the phenomena of 
the mineral kingdom, till supported by stronger facts than 
those on which it rests at present. 
