124 ON EROSIONS OF THE EARTH'S SURFACE. 



face emerged from the waters : although essentially the same rivers as existed pre- 

 viously, must have been the result of drainage. 



The grounds on which I refer the cases mentioned below and described in detail 

 in this paper to the latest of former continents are the following : — 



1. The occurrence of pot-holes in the walls of gorges, which are either dry, or 

 the bed of a brook too small to have produced them. 



2. The outlet of such gorges in one direction into valleys now containing 

 streams large enough to have formed the gorges, and in the other direction, into 

 valleys leading at a gentle descent to some rivers. 



These two facts make it certain that the gorges were once the beds of rivers. 



3. An accumulation of water-worn and, perhaps sorted materials, viz : gravel 

 and sand, to a considerable depth. This accumulation appears to me to have been 

 made during the last submergence of the land, and to be the cause that prevented 

 the ancient rivers from occupying their old channels upon the drainage of the 

 country, and compelled them, at least for a considerable distance, to find a new 

 channel. I consider the following as examples of this phenomenon, most of them 

 very decided; that is, of these antediluvial river beds. 



1. An old bed of Niagara river, commencing on the Canada shore, near the 

 Whirlpool, and passing circuitously to St. Davids, four miles west of Queenstown. 



2. An old bed of Genesee river, extending from the mouth of Irondequoit creek, 

 nearly to Rochester. 



3. An old bed of the same river, extending from Portage to Mount Morris, some 

 twelve or fourteen miles, now filled with sand and gravel. 



4. Proctorsville Gulf, an ancient bed of Black river, in Cavendish, Vermont. 



5. A former bed of Connecticut river, in Portland, Connecticut. Indeed there 

 are two such beds : but I have examined the most easterly one with most atten- 

 tion. It is near the junction of the sandstone and hypozoic rocks, and is filled 

 with gravel to the height of about 200 feet above the river at present. My im- 

 pression is that the Connecticut ran in this channel on the last continent before 

 the present, and that the detritus which was thrown into it during the last sub- 

 aqueous sojourn of the continent, turned the river into its present channel upon 

 the emergence of the land. But I am not sure that this old channel was occupied 

 by the river at so recent a date. It might have been at a still earlier date. My 

 doubts spring from the great height of the old bed above the present river. 



6. Former bed of Delaware river, along the valley now occupied by the Dela- 

 ware and Hudson canal, from Port Jervis, or Delaware, to Hudson river. 



7. Bed of an ancient river in Antwerp, Jefferson county, New York. I venture 

 to place this example among the river beds of the last continent, although I have 

 never examined it. But taking Professor Emmons' description of the deserted 

 river bed in that place, and looking at a map of the region, I venture to predict 

 that it will be found that the Oswegatchie river once ran into what is now the 

 Indian river, and was forced by the filling up of its channel when beneath the 

 ocean, to take another very circuitous route to Ogdensburg. 



8. An ancient bed of Agawam river, in Russell. See No. 10 of erosions in 

 hypozoic rocks. 



