Transactions of the Geological Society of France. 293 
in a notice of the nitrifiable chalky limestone of Roche-Guyon and 
Mousseau in the department of Seine and Oise. He concluded that 
if the chalk contains animal matter in the places from whence the 
nitre is obtained, that it is too scarce to have any influence upon the 
phenomenon. Carbonate of lime, without a trace of organic matter 
nitrifies simply under the influence of the air and of moisture. Un- 
der these influences aided by the sun, the chalk might absorb the 
principles of the air and effect the formation of nitric acid, in conse- 
quence of the production of ammonia and its action on azoted sub- 
stances. 
M. Fovrner proposes a new explanation of this curious opera- 
tion. He finds it in the united influence of water and of porous 
bodies upon the elements of the air, in order to form the protoxide 
of azote, which combined with water, can give origin to the nitrate 
of ammonia at once, by a simple isomeric action. This nitrate, de- 
composed gradually by the carbonate of lime, is converted into nitrate 
of lime and into volatile carbonate of ammonia, which is withdrawn 
by the currents of air, necessary for the developement of nitrifica- 
tion. 
Origin of Fossil Pyrites.—Iron Pyrites, and Pyritic petrifactions 
m animal carcases have never been satisfactorily explained. Since 
gelatinous matter appears to have favored the conglomeration of sil- 
ica, and consequently the formation of siliceous petrifactions, so like- 
wise the putrefaction of animal matter having produced sulphuretted 
hydrogen, if any particles of oxide of iron should happen to be pres- 
ent in the surrounding mud, pyrites would be formed, and would ac- 
cumulate about the places where the gas is disengaged. 
Origin of Amber.—M. T. Axsst has discussed anew the origin 
of amber, which he says isa resin of the Conifere. He has exam- 
ined particularly that Castrogiovanni i in Sicily, and he cites, though 
not with perfect confidence, a specimen of amber containing a land 
Shell. (Atti dell. Acad. Giwn. di Stor. nat. di Catania, vol. 6, 
p. 17.) 
M. Grarrenaver has also given to the Strasbourg society of the 
Sciences, a monograph on amber, which he supposes to have origi- 
nated in extinct species of trees. 
Origin of Sulphur —C. Gemexuaro has read before the Acad- 
omy of Catania, a memoir, entitled a new theory relative to the ori- 
gin of sulphur. He supposes that it originates in the decomposition 
of naked mollusca, and that being acidified by the action of subter- 
