EROSIONS. 211 



which we have met in the barriers of ancient lakes. We might, however, suggest a third 



cause in th( 



continents. 



cause in the flux and reflux of tides and currents during the slow vertical movements of 



THE GORGE AT BRATTLEBORO. 



Wantastoquit Mountain rises precipitously on the east bank of Connecticut River, 

 opposite Brattleboro, to the height of 1050 feet, while on the west side the hills rise 

 higher and higher, till they culminate in the crest of the Green Mountains. The top of 

 Wantastoquit also shows marks of river action more decidedly than Kilburn Peak. In 

 short, the circumstances at the two places scarcely differ, except that the hills on the west 

 side rise less rapidly at Brattleboro. But we can hardly doubt that the Brattleboro gorge, 

 like that at Bellows Falls, has been slowly eroded by fluviatile and oceanic agency, and 

 that the narrow and rather irregular valley between the two places was once a deep lake. 

 And we might say the same of several other basins on the Connecticut, where at the ends 

 the mountains crowd close upon the river. The case at Bellows Falls is the most remark- 

 able, because we find the exact place where the lake had once an outlet towards the east. 

 But if we make out erosion there, no one need hesitate to admit it at any other place along 

 the river, since everywhere else almost it must have been on a smaller scale. 



ANCIENT RIVER BEDS IN CAVENDISH. 



This case was described a few years since in a work on Surface Geology, already referred 

 to frequently, and we take the liberty to transfer that account to the present Report. 



Williams River and Black River, streams of nearly the same size, rise in the Green 

 Mountains, and, running nearly parallel, empty into Connecticut River the former two 

 or three miles north of Bellows Falls, and the latter ten or eleven miles further north. 

 Through most of their course, they are separated by mountains rising sometimes to near 

 a thousand feet in height. Yet there are at least two gulfs, the Duttonsville one, and 

 that at Proctorsville in Cavendish, connecting the valleys of the two streams, and through 

 which Black River once flowed into Williams River in other words, it is probable that 

 Black River was once a tributary of Williams River. The evidence of the position I 

 shall now present. 



THE DUTTONSVILLE GULF. 



The Rutland and Burlington Railroad passes up Williams River from Bellows Falls, 

 eighteen miles to Gassett's station. There it turns to the right, and crosses to Black River 

 through the Duttonsville Gulf. Through its whole course that gulf bears evidence, to a 

 practiced eye, of being the former bed of a river; but just before we reach Duttonsville 

 we find deep pot-holes in the gneiss rock, perhaps fifty feet above Black River. This 

 old river bed, especially near Duttonsville, is choked up to the depth of several feet by 

 terrace materials which must have been deposited during the last submergence of the 

 continent beneath the ocean. These formed a bank so high that as the surface emerged, 

 and a river began to run down the valley, it was turned to the left, and found a new channel 

 to the left of the mountain lying east of Duttonsville. The following sketch, taken by the 

 eye, will present an outline of the spot, 



