No. 50.] 
53 
In the more recent limestones, comparatively few minerals have been 
found, and these seldom belong to the rarer species. As has alieady 
been observed, the Trenton limestone series contains in various locali- 
ties, and especially in Levv^is county, unimportant veins of galena, iron 
pyrites, fluor and calcareous spar. 
Geodiferous Limestone. — This rock extends over some of the west- 
ern counties, and has been thought to be sufficiently characterized by 
the numerous geodes which it contains. These geodes, though usually 
small, are sometimes of considerable size, and contain the sulphates of 
barytes and strontia, sulphate of lime, in several varieties, fluor spar in 
limpid and colored crystals, arragonite and pearl spar, besides the most 
beautiful specimens of dog-tooth spar. Sulphuret of zinc, galena and 
bitumen, have also been found in this rock — the latter in such quan- 
tity as to warrant the conclusion, that the peculiar odour which this 
rock so frequently possesses is due to the presence of that mineral sub- 
stance. To these may be added, some of the ores of copper, found in 
exceedingly minute quantities, and sulphate of magnesia, in an efflo- 
rescent form, arising from the decomposition of the carbonate of mag- 
nesia which the rock contains. 
In the Water Limestones, we have some interesting minerals. — 
Among these may be enumerated various forms of calcareous spar, and 
yellow sulphuret of zinc, as at Kingston, Ulster county; carbonate of 
strontia, and other species containing barytes and strontia, as at Scho- 
harie ; purple fluor, as at Manlius, Onondaga county, &c. 
Finally, in the Saliferous group, or Protean group of Mr. Vanux- 
em, we have the beds of argillaceous iron ore, with the accompanying 
minerals, the great gypseous deposits, and the extensive formations of 
calcareous tufa, in all their diversified characters. These rocks also 
constitute the repository of the numerous and important brine springs 
of Onondaga and Cayuga counties. 
Such is a brief outline of the mineral contents of the principal rock 
formations of this State. Imperfect as it is, it may serve as a guide to 
those who are desirous of studying our mineralogy in connexion with 
geology. One fact is here too obvious not to be particularly noticed ; 
and it is that the most abundant mineral deposits are found in the pri- 
mitive limestone, and generally near the junction of that rock with the 
granitic ranges. Whether this is owing to the agency of heat, to which 
