22 SURFACE GEOLOGY. 



bank above them, the Ashuelot cut through them, and formed lateral terraces 

 along its margin. On the northern side of the stream, at its mouth, a rocky hill 

 extends nearly or quite to the Connecticut, which is thereby forced at this spot to 

 make a curve westward. The section No. 25 passes across the Ashuelot near its 

 mouth, directly through the village, northwesterly over the hill, and then descends 

 towards the Connecticut; so that all the terraces on it to the right of this hill belong 

 to the Ashuelot ; while those to the left belong to the Connecticut. The difference 

 in their height and size on the two rivers affords a good illustration of the fact that 

 the larger the river the higher the terraces. The character of the materials, too, 

 illustrates another fact, viz., that they are coarser on small and rapid streams than 

 on larger and more tranquil ones. Excepting the lowest, which are narrow, the 

 terraces on the Ashuelot are all gravel, mixed with sand, and often the fragments 

 are quite large ; while on the Connecticut are no pebbles of consequence, but sand 

 underlaid by a thick bed of clay. A third circumstance deserves notice : On the 

 Ashuelot the terraces have a rapid slope towards its mouth, corresponding to that 

 of the river, which here falls so much as to afford a good site for manufactories ; 

 whereas, on the Connecticut, the eye cannot perceive that the terraces are not 

 strictly horizontal. Indeed, they probably decline but little from Brattleborough 

 to this place, and the two higher ones are nearly continuous between the two 

 places. The higher terrace along the Connecticut, not measured, is sandy and 

 irregular, and more properly deserves the name of a beach. 



26. This section (Plate II) is on the west side of Connecticut river, in the north 

 part of Vernon, and differs but little from that already described on the same river 

 in Hinsdale. The height of the fourth terrace, however, is greater; but the spot is 

 not a great distance south of the gorge in the river at Brattleborough, and hence 

 we should expect a greater amount of terrace materials. 



5. In the narrow Basin from Brattleborough to Bellows Falls. 



So narrow is the valley between Brattleborough and Westminster, that it deserves 

 the name of a defile rather than a basin. And yet terraces are found nearly the 

 whole distance, though usually quite narrow. Opposite Brattleborough, on the 

 east side of Connecticut river, West River Mountain rises very precipitously to the 

 height, above the river, of 1050 feet, as I ascertained by a not very accurate mode 

 of observation. On the west side of the river, the hills rise more gradually, yet 

 the rocks press closely upon the bank. Within a distance of not over half a mile, 

 two tributary streams empty into the Connecticut; the most northerly called West 

 river, of considerable size ; and the one at the south end of the village, small, and 

 called Whetstone brook. Such streams, debouching in such a spot, and at right 

 angles to the course of the Connecticut, are sure to produce numerous terraces. 

 So numerous are they, and so complicated, that I judge it necessary to devote a 

 map to them alone, so far as I have traced them out (see Plate V;) for I have 

 not obtained quite all the facts in respect to the sections that would have been 

 desirable, yet I have enough to be very instructive as to river terraces. 



27. This section (Plate II) commences on the west bank of the Connecticut and 



