KOlTJEN-STOXli:. 
35 
tor this really seems to be the state, in which the greater part 
of the indurated rotten stone occurs. To this objection, I can 
only, at present, oppose, as probable, the supposition, that, 
during the formation of hard rotten stone, while loosing the 
calcareous particles, a gradual and considerable contraction took 
place in the remaining matter ; and that this was effected with- 
out destroying the slaty structure, where it previously existed, 
in the primary stone.* By this assumed contraction in the 
strbstance of rotten stone, it is evident, we may readily account 
fur the greater proportion of alumine it exhibits, on comparing 
a gtven quantity of it with an equal one of limestone. But it 
will, probably, be advanced, tl.at the hypothesis eventually 
•upports mote than we wish to prove j as, admitting the con- 
traction of the matter forming rotten-stone, any limestone 
holding a smad (|uantity of alumine, may be the original stone. 
The Inca! circumstances, however, attendant on rotten stone, 
must prevent such a supposition from being adopted. All 
limestones, it is true, ate liable to decomposition } and the 
black seem to be more subject to this processf than the lighter. 
* A nearer approxiniatidii of the almniiinus partirlis to each other, 
may easily be supposeil as a ii.itnral consequence of the removal of 
the cale.Treoii>i ni.ittei , but that the slriictiire of tlie original stone 
should remain, after this loss of matl«r, will not, perhaps, be as easily 
supposed or admitted. However, as the ingredients of black lime- 
stones. Jtc. exist (it is probable) merely in the state of tnislure, the 
extraelion of any one of these constituent parts will certainly be less 
liable to destroy the general striictureof the stone, than if the process 
bad to act on principles chemically united. • 
We have here considered the structure, or fracture of hard rotten 
stone to be immediately derived, generally speaking, from that of the 
original limestone ; but in sonic instances, particularly where the slaty 
structure is present, it is rather, perhaps, the consequence of the 
contiacli'in contended for, than the remains of any particular dispo- 
sition of particles, which existed in the primary fossil. We have, not 
unfrequently, observed the slaty structure in hard rotten stone, wlrere 
no vestige of it appeared in the enclosed tmcM of limestone; though, 
it must be observed, that these nuclei, in every other respect, were 
perfectly similar to those in which such structure was very evident. 
t Vide Note. 
Th« 
