214 



OLD RIVER BEDS. 



I. IN MODIFIED DRIFT. 



It is frequently easy to see in alluvial meadows that the river has changed its bed, 

 sometimes by slowly wearing away one of its banks, and sometimes by suddenly shifting 

 to a new channel in consequence of some obstruction. In such cases the proof is obvious 

 to the eye, but not easy to describe. We see on the spot where the old bed parts from 

 the present one, and can follow it all the Avay to where it rejoins the same. These changes 

 may sometimes be seen in some of the old terraces, as at Bellows Falls and White River 

 Junction. The following cases have been noticed by us under this class. 



1. ALONG CONNECTICUT EIVER. 



1. At Bellows Falls, west part of the village. 



2. At White River Junction, proceeding from White River and passing southerly so as to join the Con- 

 necticut ; made evidently by White River. Marked on the Map of Connecticut River terraces. Plate III. 



3. At Windsor, north of the village, half or three quarters of a mile long. Others, we think, occur 

 between Windsor and White River Junction. Plate IV. 



4. In Hanover, N. H. See Map of the Connecticut. Plate III. 



5. In Orford, N. H. 



6. In Newbury are several in the beautiful meadow. See Map of the terraces there. Plate V. 



7. At Guildhall. See Map of the Connecticut. 



8. At Colebrook, N. H. See Map of the Connecticut. 



Others occur north of Colebrook, but were not observed carefully enough to be described. 



2. ON PASSUMPSIC RIVER. 



In Lyndon, a mile long, near the depot village. The old bed rather belongs to a tributary. See Map of 

 the terraces on the Passumpsic. Plate VI. 



3. ON POULTNEY RIVER. 



Prof. Adams in his second annual Report, p, 156, has given a detailed account of a remarkable change 

 effected in this river, three miles northwest of the village of Fairhaven, during a freshet in 1783. 



See Fig. 102. The river previously had run through a rocky gorge over 

 a fall, because probably its old bed on a previous continent had been filled 

 with sand. But having been diverted back again, by human agency it is 

 said, into the sand, it soon cleared out its old channel and left the falls 

 dry. The case is very similar to the sudden drainage of a pond in Glover, 

 described in another place. B is a hill of talcoid schist. A A A, an al- 

 luvial plain. S S, a neck of land, across which a man run a furrow and 

 occasioned the change in the river, a a, the dry falls, 150 feet high. 

 The old bed, mostly through rocks, extends from X, through r, to a a : 

 but a small stream, m r X, occupies a part of it and empties into the 

 present river at X. This now runs in the direction of o X S S o : the 

 present falls being at the last designated spot. C C, is an island in the 

 old channel. 



3. On Williams River, at Bartonsville, a similar case occurred in conse- 

 quence of a cut through a terrace by a railroad. A freshet cut away the 

 rest of the terrace and turned the river into its old channel, whereby a 

 mill was left dry and its owners recovered damages from the road. 



4. ON WINOOSKI RIVER. 



1. At West Waterbury. The railroad passes through it. 



2. At Waterbury. See Map, Plate V. 



3. At Middlesex. The railroad runs through it. 



5. ON THE LA MOILLE RIVER. 



1. In Fairfax. See Map, Plate V. 



2. In Johnson, east of the village ; one mile long, north side of the village, running round a large terrace. 



FIG. 102. 



