or less lamellar. It forms almost the whole of secondary countries, 
in which it presents a compact structure. In tertiary formations it is 
also very abundant, yellowish, loose, and more or less solid.~ To tu- 
fas, and concretions, which continue to be found on the surface of 
the globe, it is not less predominant; finally, it enters into amen 
position of a great number of ‘organized bodies. 2 ae 
_ The variety of forms presented by carbonate of Sebeal is immense, 
but they may all be arranged in two classes. The first, whose 
primitive form is a rhomboid—belonging to substances properly call- 
ed calcareous ; the second, whose primitive form is a righ ; 
dal prism, belonging to Arragonite. eee 
The circumstances which determine the crystallization are un- 
known. All we know is that Arragonite is found in particular beds; 
(aslotaies or anaes regions, ) which may influence its formation. 
Wh d , nothing g is more easy than 
to ) distinguish one from the other by cleavage, the measurement of the 
angles, and by the hardness ; but when they are not crystallized we must 
have recourse to a sintaatlaa process, which M. Becquerel points out, 
and by which he proves that flos-ferri, the concretions called d Tivoli _ 
sugar-plums and batberlee white marble, present the rhomboidal cleav- 
age, while fist lactites, alabaster of montmartre, &c. present that 
of Arragonite. M. Becquerel describes an apparatus by which, with 
electrical forces, he crystallizes Arragonite. He obtains the form of 
a quadrangular prism with two dihedral summits; it is that under 
which nature presents it. The same apparatus serves to form the 
double crystallized carbonate of lime and magnesia, (dolomite,) the 
protoxide of copper, and the blue and green carbonates of copper+ 
Analysis proves that the crystals of Arragonite which he has obtain- 
ed, have absolutely the same composition as those of calcareous spa" 
and differ from it only in crystallization.— Rev. Ency. Juillet, Juillety YOS2: 
GEOLOGY. ia ice a ie 
1. New cave of Bones.—An account of this cave was Tr" read by 
l de Serres to the French Academy on the 28th of May. © . 
exists in the environs of Mialet near Anduze, department du 
The principal cave has been long known, having served as a Te- 
treat for the Camisards, who had made a kind of fortress of it, in 
cases of sudden attack. It had frequently been visited by —_ 
peg but ey — until dates of — enna 
