TERRACES AROUND A WATERFALL. 735 



earth's rotation always tends to wear its right bank. Accordiuglv', it is 

 interesting- that the river has constantly made and cut off oxbows on the 

 west — that is, the right side — and never on the east side. It has successively 

 cut off four bends in Hatfield and three in the south part of Northampton, 

 and has also made the great Hadley bend, whicli it has long threatened to 

 change, into an oxbow, and it has never made great bends out to the eastward. 

 The same testimony also comes in a striking way from the tributaries 

 I have for several years given, as practical work for advanced students, the 

 mapping of portions of these tributaries of the Connecticut, which run for 

 long distances out over the old lake bottom, and on counting up the sharp 

 bends and oxbows on the right-hand side of the stream the proportion was 

 as great as 30 to 1 in favor of this side as against the opposite. 



RIVER TERRACES AROUND A RECEDING WATERFALL,. 



The flood plain of a river tends to reach the full height of highest 

 flood, and on approaching a fall this height diminishes greatly, as the waters 

 as they go over the fall, because of their increased rapidity, rise to only a 

 small fraction of their normal heiglit. At the foot of the fall or at the mouth 

 of the canyon below the fall the flood plain begins again at a level as mucli 

 below that above the fall as the descent of the waters demands. 



Thus at Turners Falls the flood plain above the falls is only 7 feet 

 above the level of the waters, and the height above the waters before the 

 erection of tlie dam was probably not many times greater, while the flood 

 height of the river here is 30 feet. If now the falls recede, leaving remnants 

 of this low flood plain, it will hang over the canyon with a height above 

 the river equal to its original height plus the height of the fall ; and this is 

 the case at Turners Falls and at Holyoke, where the old flood plain is con- 

 tinuous from above the falls south along the sides of the gorge formed by 

 the recession of the falls. 



If, further, the stream by its oscillations below the falls builds a flood 

 plain at the lower and newer level, we have the curious result that the 

 flood ])lain above the falls will extend downstream above the flood plain 

 below the falls, the two thus overlapping at two different levels. Distinct 

 traces of this appear at both of the falls on the river, especially at South 

 Hadley Falls, where the flood plain of the river is continued out over 

 the lower one for a long distance. This makes a difficulty in coloring 



