48 SURFACE GEOLOGY. 



the powerful current that once crossed this spot. It will be more particularly 

 described in my paper on Erosions. 



3. In Cavendish, Vermont. 



On Plate III, Black river and William's river, in Vermont, are seen to run 

 nearly parallel courses. It appears that they were once united: at least the prin- 

 cipal branch of Black river formerly ran southerly into the present bed of Wil- 

 liam's river. Whoever will pass through " Proctorsville Gulf," in Cavendish, shown 

 on Plate III, as an old river bed, will be satisfied that it was indeed once the 

 channel of Black river. Its present summit, raised considerably by detritus, is (by 

 the aneroid barometer) 792 feet above Connecticut river, at the top of Bellows 

 Falls, and about 100 feet above the Black river at Proctorsville; so that if this 

 river were 100 feet higher at that spot, it might run through the gulf. The sides 

 of the "gulf" are quite steep and high, resembling the banks of many of our 

 mountain streams that have been worn deeply by water. 



At Duttonville, in Cavendish, two miles lower down the stream than Proctors- 

 ville, is another more obvious ancient bed of the Black river. This, also, is filled 

 with detritus where it branches off from the present bed, but within 100 rods of 

 that spot, on the route of the Rutland and Burlington Railroad, we find large 

 and distinct pot-holes ; the infallible mementos of a former rapid current. This 

 old bed may be traced some six or eight miles towards Connecticut river, where 

 it unites again with the present channel of Black river. By the detritus which 

 chokes up the old bed, at Duttonville, that river was compelled to turn to the left, 

 where it has worn out a gorge through the rocks nearly 100 feet deep, producing a 

 romantic cataract, called Great Falls; the foot of which is 183 feet below the old 

 river bed. These two cases, belonging as they do in part to antediluvian agencies, 

 will be described again in my paper on Erosions. 



4. On Dee7-field River. 



One of these occurs near Shelburne Falls, in Buckland, where pot-holes exist in 

 the sides of the old channel, 80 feet above the present stream, as may be seen on 

 Plate IV. But a description of the spot is reserved for my paper on Erosions. 



Where Deerfield river debouches into the valley of Connecticut river, from its 

 mountain gorge, it has formed an alluvial plat of unrivalled fertility. And here 

 is displayed the best example of changes in the bed of a river by alluvial action 

 that I have ever seen. As all the early part of my life was spent in that valley, 

 I became familiar with these ancient river beds, and I have sketched them 

 in Plate IV. Some others, less obvious, perhaps, might have been added : but it 

 will be seen that not less than fourteen are put down on this spot, only four miles 

 long and one mile broad. Nay, from the manner in which rivers in alluvial spots 

 change their courses, viz., by the gradual wearing away of one of their banks, I 

 cannot doubt that every part of these four square miles, save Pine Hill, in the 



