Art. I.] Fowke, Pre-Glacial Drainage near Cincinnati 9 
per’s, the character of the deposit is clearly shown ; it is sim- 
ply a mass of detritus carried by a torrent into a body of dead 
water. The dead water was the glacial lake created by the col 
at (K) ; the torrent was that which poured through the gap 
back of Petersburg (H) in the final effort of the Ohio to carve 
out its channel. Following the north side of the base of 
'‘Kirby Rock” (which is the proper one for study, “Split 
Rock” being insignificant by comparison), it will be found that 
the large stones disappear within a few rods and are succeeded 
by cobble-stones ; these by gravel which grows smaller until it 
runs out in beds of sand; the sand, in turn, is soon replaced by 
the finest silt, resting against the limestone hill-side; and above 
this there is nothing resembling glacial drift, as far as the brow 
of the hill. 
Of what may be on the table-land, I have no knowledge. 
In the report of the Indiana Geological Survey for 1878, it is 
stated that the hill-tops south and south-east of Middle creek — - 
which enters the Ohio opposite Rising Sun — are capped with 
conglomerate similar to that at “Split Rock.” I did not know 
of this at the time of my visit to the locality ; it is probably 
due to ice-berg deposits at the beginning of the overflow at (K), 
Four miles below Grant’s creek (J) the Ohio valley is quite nar- 
row ; on the Indiana side evenly stratified glacial material is 
piled to the height of at least 100 feet. It is of the same gen- 
eral character as the terraces existing throughout the valley of 
the Ohio and many of its tributaries, and is what is usually 
classed as belonging to the “ Champlain period,” following the 
“glacial period.” The name is immaterial ; but it is an error 
to suppose that the one era ended before the other began. On 
the contrary, they were synchronous ; as soon as the outlet of 
old Kanawha was blocked glacial debris began to settle in the 
resultant lake-bed. The old river-beds were filled with it to a 
higher level than it is now to be found. Had there been no 
subsequent drainage, these valleys would now be plains having 
practically uniform surfaces. The present streams, however, in 
winding their way from side to side through them have alter- 
nately cut down and filled up, exactly as we may see every day 
