A416 J. D. Dana on some modern Calcareous Rock-formations. 
constantly used in chemical analysis, on this very account, for 
separating alumina, peroxyd of iron, &c., from any solution in 
which a soluble salt of lime is present, by adding an excess of 
the volatile alkali. Again, in one step, the bicarbonate of lime is 
formed, and in the next, hydrate of lime for the purpose of ce- 
mentation: But would not the hydrate at once change the bicar- 
bonate to carbonate again? So says chemical science. 
We have followed the theory far enough. The reader may 
be prepared to doubt Professor Horsford’s first and second infer- 
ences on page 253. “Infiltration of finely powdered (not dis- 
solved ) carbonate of lime” and “ mucilaginous matter” can hardly 
be admitted as the means of solidifying the “submerged oolitic 
rock ;” and the “chemical decompositions and recompositions” 
detailed are not attributable to nature’s elaborations. 
The second part of the memoir, bearing upon the origin of the 
lime of corals, remains for consideration. 
n page 252 it is said, that “the total want of carbonic acid 
in a water in which coral life is so luxuriant suggests naturally 
from the plant and animal yielding carbonate of lime quite in 
soluble, and sulphate of ammonia of the highest solubility.” 
The objections to this sentence are as follows. 
1. Facts show that there is not a total want of carbonic acid 
(or carbonate of lim@#in sea water about coral reefs. . 
2. The stone plant and coral animal are spoken of as distinet ; 
whereas, in fact, the stone plant is contained within the ani 
and is a part of it, and has no independent functions, and no mode 
of increase except such as it receives through secreting action 
within the coral animal. 
3. The excreted carbonate of ammonia must either produce 
the carbonate of lime in the water about the animal, or within 
the tissues immediately where the secretions take place. If the 
ormer, the waters could not show the “total want of carbonic 
in nature, until its life and growth have ceased. Such a mod 
of growth by accretion would be indicated by the absence of all 
cellular structure, and by a crystalline texture in the deposition: 
but a thin slice of coral examined with the highest magnifying 
