198 
GEOLOGY OF THE THIRD DISTRICT. 
Between the different parts of the Ontario division, no striking point of superposition was 
noticed in that section of the district; the one of most interest, was the connection between 
the Grey and Medina sandstone on the west side of the river at the village of Oswego, where 
the two rocks show an interchange of each other’s color. The Grey sandstone extends from 
the lake toward the dam, near which, at a higher level, the Medina sandstone is seen, the two 
rocks having a slight dip south. 
No. 1. Grey sandstone. No. 2. Medina sandstone. No. 3. Alluvial. No. 4. Lake Ontario. 
The only parts of the district where the Medina sandstone, the Oneida conglomerate, or the 
sandstone which represents this mass, and the Clinton group, are nearly in juxtaposition, is 
in Cayuga county. The best point for observation is at Bentley’s quarry on the road from 
Martville to Hannibalville. There the Red sandstone and the Clinton group are within a few 
feet of each other, having a grey sandstone intervening, which is intermixed with the green 
shale of the Clinton group, presenting the same characters and the same position as the grey 
band of Rochester. The Medina sandstone forms the lower part of the quarry, and the two 
other masses the higher; the junction between the red and grey sandstone is concealed by 
drift, etc. No section was prepared of this quarry, by mere omission. 
South of the Mohawk, through Herkimer county, etc., the hills and ravines afford fine 
sections of the connection between the masses from the conglomerate upwards, this rock 
through all that part resting upon the Frankfort slate. 
63. 
Section north and south from Fulmer valley, by Fox, hollow and Crugar's mill, etc., south in the towns of German-flalts 
and Warren. 
No. 1. Exhibits the Frankfort slate, etc., which forms the bottom of the valley 
2. Oneida conglomerate. 
3. Clinton group, with the grey sandstone mass at the top under the mill. 
4. Red shale, and other masses which belong to the Onondaga salt group. 
5. Water-lime group, quarried to the south of Mr. Crugar’s. 
6. Pentamerus limestone, forming the top of the two hills south of the quarrry on the road to Richford’s springs. 
