368 
FROM NICHOLAEF, 
chap, found in the Iceland spar, and as accurately 
— ) corresponding with the obtuse angle of that 
mineral as if they had been regulated by the 
goniometer. Before Saussure discovered strata 
of limestone lying beneath rocks of the most 
autient formation, the French endeavoured to 
establish a theory, that all the carbonated lime 
upon the surface of the globe resulted from 
the decomposition of animal matter, deposited 
during a series of ages. Whosoever has at- 
tended to the appearances left by testaceous 
animals, particularly in the cavities of the Cornu 
Ammonis, must have been struck with the 
remarkable circumstance, that where an escape 
of the fleshy part of the animal has been pre- 
cluded by the surrounding shell, pure and 
perfect crystals of carbonated lime have been 
formed ; and must also frequently have remarked, 
that shells alone, independent of the admission 
of any extraneous substance, have, by their 
deposit, constituted immense strata of limestone. 
For the truth of this, it is unnecessary to ad- 
duce a more striking example than the instance 
afforded of the limestone in the neighbourhood of 
Odessa. It is in a semi-indurated state; but, 
like the Ketlon-stone', and almost every other 
(l) This stone, by a very recent analysis of the Rev. J. Holme , of 
*SV. Peter's College , Cambridge , is found to be one of the purest 
combinations of lime and carbonic acid. 
