Al Review of the New York Geological Reports. 
Of these, the third is the only one that has yielded gypsum in 
profitable quantities. ‘The included masses of gypsum, though, 
for the most part, even-bedded at their base, are usually very ir- 
regular at their upper surface, often conical. The plaster beds 
are supposed to be segregations by molecular attraction from the 
marl. Might it not have originated in the introduction of subter- 
ranean springs, charged with sulphuric acid or sulphates, bursting 
up through fissures in the inferior strata, and mingling with the 
waters of the ocean holding lime in solution, by which mounds 
and irregular beds of the resulting precipitated sulphate of lime 
would accumulate, isolated in a great measure from the deposites 
of calcareous mud going on around? Most of the gypsum is of 
a dull earthy color, and it usually effervesces with acids from the 
presence of carbonate of lime. 
This third division contains not only the gypseous beds, but is, 
most probably, the source also of all the salt so extensively manu- 
factured at Onondaga, Cayuga and Madison ; at least Vanuxem in- 
forms us, that, except in these gypseous beds, there is no evidence 
of salt existing in the solid state in any of the other divisions of 
the Onondaga salt group. This author believes that the hopper- 
shaped cavities situated between the two plaster beds prove that 
salt has crystallized during the desiccation of the waters in which 
the surrounding deposite of argillaceous and calcareous matter 
was going forward, since, during the evaporation of brines, cubes 
of salt aggregate so as to form groups of crystals corresponding 
perfectly to such a matrix. Near the same geological position is 
the Vermicular lime rock of Earon, so called from numerous, 
disseminated, tubular cavities, which Vanuxem thinks are also due 
to previously existing common salt. 
The fourth division is remarkable for a fine columnar struc- 
_ ture or needle formed cavities dispersed through the mass. These 
Vanvxem believes to have been caused by erystallizations of sul- 
phate of magnesia during the consolidation of the rock, and sub- 
sequently removed by percolation of water; for this reason he 
has denominated this part of the Onondaga salt group the “ Mag- 
nesian deposite,” and its cavities “ Epsomites.” 
_ Connected with this formation, “between the two porous mass- 
es,” the geologist of the third district has described “a mass of 
uter ec ‘rock extending for many rods,” which in structure par- 
