338 . bulletin: museum of comparative zoology. 



A few special features deserve mention. A southward deflection of 

 the stream from ledge K, and an increasing southward meander of the 

 stream in consequence of this deflection, with a southward swinging of 

 such a meander, has probably been responsible for some of the large 

 re-entrants on the south side of the basin ; but it is not yet apparent 

 why the re-entrants on the north should have been repeatedly worn 

 farther from the line between the nodes than on the south. The vari- 

 ous combinations of two-sweep cusps in the group of nine stepping 

 terraces next down-valley from ledge C is in every respect confirmatory 

 of the deductions (page 309). It is notable that remnants of terraces 

 at intermediate heights form little recesses in the cusps of later origin, 

 as might have been expected. The terraces in the wooded slope south 

 of C have not been traced out ; but a little farther east four low-scarped 

 terraces rise at D above the plain that forms the top of the nine-step 

 flight, thus making a series of thirteen steps. Curiously enough, these 

 four upper terraces, forming the upper members of the longest flight 

 that I have yet counted, swing northeastward from what seems to be 

 a free cusp, thus apparently imitating conditions similar to those of 

 Figures 15 and 17. No ledge is visible in the front of this group, but 

 as the scarp of the ninth terrace, here descending to the seventh, also 

 bows a little forward directly in front of the apparently free cusp, I am 

 much inclined to think that there is really some defence here, now 

 masked by a slipping drift cover. A soil augur test is proposed to settle 

 this doubt. A detailed map of this basin and its terraces would be well 

 worth preparing. 



The Connecticut below Bellows Falls, Vermont. The Connecti- 

 cut river at Bellows Falls is superposed on a large body of rock, on 

 whose down-valley side the river is narrowed in rushing cascades and 

 rapids. A mile farther down-stream, three fine terraces are developed 

 at A, Figure 42, on the west side of the valley just below the mouth of 

 Saxtons river, S, and all seem to be defended by ledges ; the upper two 

 by ledges of the large rock ridge at the mouth of Saxtons river (these 

 are marked N, in Figure 41), the lowest by a ledge that stands several 

 hundred feet farther forward and is seen in the railroad cut a quarter of 

 a mile south of Saxtons river. This group of terraces is shown as seen 

 from the southeast in Figure B, Plate VIIL, of Russell's " Rivers of 

 North America." A little further south, the two lower terraces are 

 cut away westward in the formation of a broad valley floor, B. A full- 

 height scarp rises at the back border of the floor, and near its middle is 

 a blunt cusp determined by a strong ledge. The southern end of this 



