HELDERBERG DIVISION. 
353 
9. Onondaga Salt Group. 
This group of rocks, which is so largely developed in the central portion of the State, thins 
out in the First geological district, so that in many places it is absent; and where it is found, 
it is but a few feet in thickness. 
The grey and porous yellow limestone of this group was recognized by P/of. Vanuxem at 
Sharon springs, overlying the Frankfort slates, and underlying the Helderberg series, opposite 
the mill, two hundred or three hundred yards north of the springs. 
No salt water has been found in this group of rocks in the First district, unless the boring 
for the salt well on Fox creek, near Delhi, in Delaware county, penetrated into these rocks. 
IV. ONTARIO DIVISION. 
The rocks under this division may be classed under two groups : 
1st. The 'pyritous strata and red shales and grit; 
2d. The Shawangunk grit^ or conglomerate; and a 
3d. A range of rocks similar to the above, but the identity of which is not completely demonstrated. 
1. Under the first of the above groups are included some thin strata lying between the 
Water-limestone group and the Shawangunk grit rock. These strata are frequently wanting 
altogether in the First geological district, and the thickness is less, generally, than thirty feet. 
The pyrites, in some cases, is found in the limestone, and sometimes in the Shawangunk 
grit, but usually in the intervening strata of greenish and red slate and shale. 
At High falls on the RondouHn Marbletown, Ulster county, the pyritous stratum, which 
is there a slaty bluish limestone, occurs above the red shales that overlie the Shawangunk 
grit. The following is a section of the rocks at that place, above the bridge, and near the 
bend of the creel^, on its left bank below the falls. 
1. Cement rock_ 12 to 15 feet. 
2. Limestone__ 10 to 30 “ 
3. Cement rock_ 6 to 8 “ 
4. Pyritous slaty limestone - 4 to 10 “ 
5. Red shale with green spots, containing nodules and crystals of pyrites, and 
thin bands of grey compact limestone_ 15 to 20 “ 
6. Conglomerate or Shawangunk grit, unknown thickness. 
Geol. 1st Dist. 
45 
