Man and f/ie (rlackd Period. 201 
the drift gradually increasing until it is 200 feet and over in 
depth. Here, too, is an immeuse deposit of gravel, and at this 
point the Big Miami river enters, flowing in another wide valley. 
Together these united valleys turn southwest and after following 
& meandering course for some 20 or 25 miles, enter the present 
drainage of the Ohio near Valley Junction. In the course of 
this valley there are again enormous water deposits, and at its 
mouth is another phenomenally large gravel and till deposit. 
Down this valley another tongue of ice must have extended and 
blocked the Ohio channel again. 
It is a peculiar fact that between the mouth of Mill creek and 
the Big Miami river there is not a stream of any length entering 
the Ohio river from either north or south. We find, however, 
opposite the mouth of Mill creek, on the Kentucky side, that 
while rock is exposed immediately on the river's edge, below it, 
and a short distance back, less than one-eighth of a mile, is a 
high, almost isolated hill, composed of drift material. Further 
down the drift is piled up against the lower part of the north side 
of the rocky bank, but it tails out to nothing before reaching the 
top, some 350 feet above low water. Down the river from this 
hill, again, is a great embayment, and here we find still another 
deposit of water-worn gravel, this time not in a valley- occupied 
by any stream at present. It was possibly deposited from the 
Mill creek valley, down which a third ice tongue must have come, 
uniting with that from the Little Miami valley. 
Opposite the main part of Cincinnati, on the Kentucky side, 
the Licking river enters the Ohio. Here we have another of the 
wide valleys so characteristic of the region, one out of all pro- 
portion to the size of the stream now occupj'ing it, and bounded 
by rock banks on either side. This would allow the tongue of ice 
from the Little Miami valley to find egress to the south without 
having to surmount the tops of the hills. The water from the 
melting ice would probably find its way along the upper valley of 
the Licking, and, overtopping the low divide, enter the drainage 
area of the Kentucky river and so reach the Ohio below the dam. 
The main stream of the Ohio, meanwhile, was deflected from its 
course higher up, and may also have entered the drainage of the 
Kentucky river. 
Now, the retirement of the ice up these valleys would account 
for several facts. (1) It would explain the great deposit of 
