294 The American Geologist. November, 1894 
old valleys. A characteristic of the former drainage is the 
til ling of the ancient channels, above which the modern streams 
Mow upon the accumulation of drift. The ancient valleys are 
relatively much shallower but broader than the modern, with 
sides more sloping and other marks of greater antiquity than 
the modern streams, where they have cut new channels in 
place of reopening the buried valleys. 
7. "Reversal of the Drainage of the Upper Ohio and other 
rivers. Among the earlier studies on buried valleys were those 
of Dr. J. S. Newberry, Dr. T. Sterry Hunt, and Mr. J. F.Carll. 
To Mr. Carl! belongs the credit of first working out the re- 
versal of the drainage of western Pennsylvania, where he dis- 
covered that the upper Allegheny and some other streams 
flowed into the Erie basin before the Pleistocene period. In 
1881 the writer, following Carll, pointed out that there is ev- 
idence that the whole upper Ohio river, above the Beaver 
tributary, flowed to the Erie basin. This hypothesis was am- 
plified by Dr. P. Max Foshajr, and later the observations have 
been extended by Prof. T. C. Chamberlin and Mr. Frank Lev- 
erett, confirming the change in the direction of the drainage. 
The streams south of lake Erie generally drain a much smaller 
basin than formerly. So in New York, the upper waters 
of the Susquehanna, and of its tributaries, drained to the 
north into the Ontario basin, by way of the Finger lakes, 
which now occupy the old river courses, partially closed up 
by drift deposits and by terrestrial warping or deformation 
towards the north. 
8. Closing of the Valleys into Lake Basins. The old Lau- 
rentian valley was more than a hundred miles wide, but it was 
interrupted by the deposition of drift in many places, most 
notably between Georgian bay and lake Ontario. To some 
extent the modern St. Lawrence river is flowing over a drift- 
filled valley. This obstruction has caused the modern drain- 
age to be changed from the old directions and often to pass 
over rocky barriers. But in addition to the drift obstruction. 
we find that the recent terrestrial uplift has been greatest 
toward the northeast, producing barriers and forming basins. 
The warping has been measured and is found sufficient to ac- 
count for all the rocky barrier below the outlet of lake Onta- 
rio. Moreover this northeastern elevation has caused all the 
