148 NEW YORK STATE MUSEUM 
galena is found in the Trenton limestones in calcite veins, at 
Rossie and to the south galena, associated with sphalerite and 
chalcopyrite, occur in a calcite gangue in a country rock of 
injected gneiss and probably limestone; in the Beekmantown 
Limestone at Manheim sphalerite has been mined, in the Niagara 
formation of Clinton, sphalerite and chalcopyrite are found in 
calcitic geodes and again to the south at Shawangunk, sphalerite 
associated with galena and chalcopyrite in a gangue of quartz and 
a country rock of grit (Shawangunk). The fracturing and 
brecciation at the Shawangunk deposit is doubtless a product 
of the Appalachian revolution according to Newland (10) but 
as to whether the origin is due to aqueous or igneous agencies no 
definite conclusion has been reached. 
The freshness of the solution marks seen on the horse and its 
cuspidal contact line with the vein show positively that the filling 
took place in a region of active ground water circulation but 
whether it was a product of pre-Mesozoic or of post-Mesozoic 
times would be difficult to state in the present state of our knowl- 
edge concerning the subject. In other words it seems very likely 
that the filling of the vein took place either at the close of the 
Paleozoic or Mesozoic, the two great periods of mountain-mak- 
ing disturbances and when the possibilities of mineral deposition 
were greater than at other times. 
Bibliography 
1 Smyth, C. H. Crystalline Rocks of the Western Adirondack Region, 
Sist Ann. Rept, N. Y. State Mus. 2:476 
2 (a) Miller, W. J. Geology of the Port Leyden Quadrangle, Lewis Co., 
IND OYES NG RYESS tate Mitch mesa eias Sem auaTes 
(b) The Geological History of New York State. N. Y. State 
Mus. Bul. 168, p. 73 and 74 
3 Clarke, J. M. Written communication 
4 Phillips, A. H. Mineralogy. p. 391 
5 Ransome, F. L. Economic Geology of the Silverton Quadrangle, Col. 
“Wi S. Geol. Surv. Bul. 182, p. 69 
6 Dana, J. D. The System of Mineralogy. 19014 
~ Cushing, H. P. Geology of the Little Falls Quadrangle. N. Y. State 
ove Bul. 95, p. 405 
8 Van Tuyl, F. M. Geodes of the Keokuk Beds. Am. Jour. Sci. 4th 
series, v. XILIII, 1916, p. 40 
9 Van Hise, GR A Treatise of Mecamorahionn U.S. Geol. Surv. Mon. 
XLVII p. 64-67 
10 Newland, David H. The Mineral Resources of New York. N. Y. State 
Mus. Bul. 223 and 224, p. 304-07 
