OF DENISON UNIVERSITY. 
69 
tom of the Clinton Group as far as worked was at 198.21 ft.; the top, 
at 208.04 ft.; but a conjectural thickness of twelve feet would not be 
far from correct. The stone presents the usual characteristics, but 
seems to be less fossiliferous than some of the neighboring quarries. 
It is peculiar in showing fissures; extending east and west, distant from 
each other about 9 feet, found at no other station in the Clinton Group. 
In the southern part of the quarry there is a sudden dip to the south 
and the stone is broken, as though the blue clay layer beneath had 
given way and permitted the stone to sink. The fissures in the rock 
are perhaps also explained in this manner. 
The Niagara exposure is a little more than 15 feet in height. The 
base of the series is composed of broken, irregular, yellow layers of 
stone from two to five inches thick, making a total of 1.9 feet. Above 
is a 9 inch course of blue flagging stone, which was at one time 
quarried and sold in slabs for pavements. It resembles a fair quality 
of Dayton limestone of which it is the stratigraphical equivalent. 
Formerly when the Clinton stone was not exposed and the Cincinnati 
Group was in plain sight along the hill below, and the great dip of the 
rock had not yet been determined, the identity of this stone remained 
for a long time a puzzle. Above the blue flagging is a series of shales 
3 ft. thick, varying in character, sometimes represented by broken 
courses of yellow limestone 2.5 ft. thick, composed of a nine inch layer 
above and below, with the intermediate layers more or less shaly in 
character. Sometimes the remainder also becomes somewhat shaly. 
Last in the series is a 7 ft. layer of yellow^ Niagara stone, formed of 
very broken, thin courses, from half an inch to two inches in thickness, 
frequently becoming shaly. The top of the blue flag layer in the 
southern part of the quarry is at 210.70; seventy-five feet north, at 
204.10; fifty feet west, at 203.89. This would give a dip of 4 ft. 5 
in. in fifty feet towards the north, and only 2.5 in. in the same distance, 
towards the west; the last dip is reliable, owing to the very even stratifi- 
cation of the blue flagging. At the same point the bottom of the 
heavy Niagara stone is reached at 206.92; the top at 209.49. 
Farther west the top is again reached at 207.87, and the summit of the 
thin shaly courses at 214.85. All the Niagara stone here exposed is 
unfossiliferous as far as known. In some parts of the quarry the 
Niagara stone is all tumbled together, destroying its original stratifica- 
tion. I presume that the action of ice during the glacial epoch could 
readily account for this, since all the quarries round about, where the 
