10-t ON EROSIONS OF THE EARTH'S SURFACE. 



once flowed through it, and joined Williams river. Indeed, its bottom is only a 

 few feet higher than that of the ravine just described, which branches from it to 

 the left. Yet since the stream must have flowed through the lowest valley at the 

 latest period, we must regard the valley running to Gassett's as the bed of a river 

 at an earlier date. But this subject will be referred to more at length in a subse- 

 quent paragraph. 



The Proctorsville Gulf. 



The bed of the ancient river at Duttonsville is 675 feet above the top of Bellows 

 Falls. Passing from this place two miles up the Black river, we find a rather 

 broad valley almost level, as far as Proctorsville, another flourishing village. 

 Running nearly south from this village, we find a deep narrow ravine, cutting 

 through the high mountain and opening at its southern extremity into the valley 

 of a tributary of Williams river. I found no pot-holes in the sides of this 

 ravine, but every other mark of a former current of water, which wore out the 

 gorge in fact, is seen on the surface. The highest point in the gulf, perhaps a 

 mile south of Proctorsville, is 117 feet above the old river bed at Duttonsville, 

 or 792 feet above the top of Bellows Falls. At the summit the gorge shows a 

 deposit of terrace materials, how deep I cannot say. But the fact is sufficient to 

 show that no stream has passed through the gorge since the last emergence of the 

 continent. But that Black river — or rather the progenitor of that river, on a 

 former continent — once passed through this gorge, and was in fact a part of Wil- 

 liams river, will be obvious by an inspection of the rough outline on Plate III. 

 But at what period of antediluvian history did this take place ? 



If the principle above alluded to be true, viz., that where more than one lateral 

 ravine, once the beds of rivers, open from a common valley, that which is the 

 lowest was last occupied by the stream, then the Duttonsville gulf is more recent 

 than the Proctorsville gulf. I have inferred that the former was the bed of a 

 stream on the continent which immediately preceded the present. Was the latter 

 worn out during the same period ; or might it have been the work of a stream on 

 a still earlier continent, that is, the second one anterior to the present ? If we 

 knew the depth of the detritus at the summit of the Proctorsville gulf, it might 

 aid in deciding this point. But I can hardly believe that its depth equals the 

 difference of level between the two gulfs. If not, then the Proctorsville gulf must 

 have been higher than the other, during the period of emergence previous to the 

 present. The country below Proctorsville, also, must have been blocked up high 

 enough to throw the waters through the Proctorsville outlet. The amount of 

 erosion since that time, on such a supposition, must have been enormous to bring 

 the region below Duttonsville into its present state. And it would not be an 

 improbable supposition, that the Proctorsville gulf, as well as the right hand 

 branch of the Duttonsville gulf, already described, may have been the bed of a 

 stream on a continent earlier than the last. But I despair of being able to prove 

 this decidedly by any facts within the reach of present observation. And yet 

 those detailed above, do appear to me to prove at least a great difference in the 

 ages of these two gulfs. But whether the period between them embraced a sub- 



