186 THEORY. 



the Table. The elevations were all taken above the bodies of water to which the terraces 

 belonged, at the foot of the terraces. Though they are perhaps the highest terraces 

 respectively upon their rivers, they are not necessarily the highest above the ocean. The 

 highest recorded terrace above the ocean is the high terrace on the La Moille River, 380 

 feet above the river, and 1120 feet above the ocean. Higher terraces were seen even on 

 the La Moille River, but were not measured. 



2. The number, height and breadth of the river terraces, vary with the size of the 

 river, the width of the valley, and the velocity of the current above the place where tin- 

 deposits are made. Generally the number is greater upon small than large streams, 

 while the height is less. This may be seen upon the various sections. Thus the terraces 

 on the Connecticut are four or five usually ; but on its tributaries, especially where they 

 enter the Connecticut, the number rises sometimes as high as ten, as on Whetstone Brook 

 and West River in Brattleboro, Saxton's River at Bellows Falls, and Williams River in 

 Rockingham. In these cases the terraces on the tributaries are formed in the terraces of 

 the principal stream ; and though the former are more numerous, they rise no higher than 

 the latter. 



3. Terraces occur in basins both upon rivers and lakes. They may be conceived as 

 having been formed in a series of ponds or lakes, connected together by a current, like 

 the great inland lakes of North America. It is unnecessary to suppose that each of 

 these basins was limited by rocky barriers, which were gradually worn away by the river 

 itself. It has been shown that in most cases evidences of drift action may be seen near 

 the bottom of these gorges, and therefore the rock must have been excavated at or before 

 the drift period. We would not affirm that there are no cases in which the terraces were 

 formed in consequence of a barrier thrust across the valley, either of rock or drift. W"e 

 rather have affirmed, and described such cases ; and think that in such cases the basins 

 can be distinguished from the more usual forms by the equal height of the highest 

 terraces upon the different sides of the valley. 



Upon Connecticut River we have described twenty two basins, between its mouth and 

 source : Upon Saxton's River, four ; upon Williams River, three ; upon Black River, six ; 

 upon Otta Quechee River, three or more ; upon White River, at least nine; upon Pa.s- 

 sumpsic River, three or four ; upon Otter Creek, probably five ; upon Winooski River, 

 five ; upon La Moille River, five ; and some others upon the smaller streams, or those 

 that flow only a short distance in Vermont as Hoosac River, Battenkill River, Pawlet 

 River, etc. 



4. The river terraces, excepting the delta terraces, rarely correspond in number or in 

 height on opposite sides of the stream. The delta terraces wherever worn through by a 

 stream, will of course have the same height on both sides of the river. When the 

 valley is wide, and several terraces exist on opposite sides : by the eye alone, one is apt to 

 imagine an exact correspondence in height. But the application of the level usually 

 dissipates such an impression, as nearly all the sections of terraces given in the detailed 

 descriptions will show. Were these sections carried across the rivers more frequently, it 

 would have appeared that sometimes no terraces exist on one side, while there are many 

 on the other ; or that the number differs much on opposite sides. 



