ON DELAWARE RIVER. HI 



Mount Morris, since the drift period. I copy on Plate XII., Fig. 3, Mr. Hall's 

 sketch illustrative of this view. On the right is shown the present bed of the 

 river, and on the left, the ancient valley, now filled with sand, gravel, and clay. 



4. Bed of Oak Orchard Creek in Orleans county, New York.— This is a small 

 stream that empties into lake Ontario, passing across the same strata as the 

 Genesee, viz: the Medina sandstone and the Clinton and Niagara groups. As 

 we might expect, we find a similar seiies of cataracts and rapids : but I am unable 

 to give any details as to their height, distance from one another, &c. The case is 

 interesting, however, as lending additional confirmation to the views already pre- 

 sented, as to the fluviatile origin of the erosions in such streams as the Niagara 

 and Genesee. 



5. Gorge on the Au Sable River in Essex county, New York. — On the west side of 

 lake Champlain, not far from Keesville, this river has cut a passage for a great dis- 

 tance through the Potsdam sandstone, which shows strikingly the excavating power 

 of water. At Birmingham is a gorge two miles long and 100 feet deep. The best 

 place for visiting it, is at a spot called High Bridge, where stairs have been cut in 

 the walls to the bottom of the gulf, and as you stand there, the frowning and 

 even overhanging walls almost shut out the light of day. No man at that spot 

 could imagine any other agency but the stream itself to produce such a gulf. I 

 mean no man accustomed to reason upon this class of geological phenomena. The 

 average width of the gorge is only from 20 to 40 feet. 



This spot may be reached by steamboat and two or three miles land travel, from 

 Burlington, Vermont, and well repays the visitor. — Emmons' Geological Report on 

 the Second District, p. 266. 



6. Water Gap on Delaware River, in New Jersey. — Macculloch, in his Geographi- 

 cal Dictionary, states this gap to be 1200 feet deep and two miles long. I have 

 not visited the spot, nor have I been able to ascertain whether the rocks be crys- 

 talline or Silurian. 



In examining the valley in which Port Jervis and Delaware are situated, 40 

 ■•riiles above the gap, on Delaware river, I became satisfied that this river once ran 

 northeasterly towards the Hudson river. And I am informed by H. N. Farnum, 

 Esq., of Port Jervis, that the summit level of the Delaware and Hudson canal is 

 only 115 feet above the Delaware opposite Port Jervis. If, therefore, the Water 

 Gap were closed to the height of 115 feet, plus the descent of the river between 

 the gap and Port Jervis, the Delaware would be turned into the Hudson. Such I 

 can hardly doubt was the course of its predecessor on a former continent. But 

 during the last submergence of that region, the old bed was filled with gravel and 

 sand, so as to turn the Delaware towards the Water Gap, and probably some of 

 the erosion there has been effected since the last emergence* of our continent. The 

 valley of the Delaware and Hudson canal, therefore, adds another example of an 

 antediluvian river bed. I do not, however, feel so confident in this conclusion as 

 I should if I had examined the whole ground. 



7. Gorge on Delaware River from Port Jervis to Narrowsburg. — This is a deep 

 and crooked gorge about 25 miles long, exhibiting some of the wildest scenery in 

 our country, yet distinguished by two works of art of great magnitude and import- 



