DAVIS: RIVER TERRACES IN NEW ENGLAND. 331 



repeatedly turned southward on its way to the fixed node, G, in the 

 trap-ridge notch. 



Nearly opposite to this well-defended spur, hut a little further 

 westward, the free spur, B, rising to the full height of the drift 

 plain, separates the subordinate eastern basin, C, and that part of the 

 main basin, H, which has been scoured out chiefly by Little river. 

 Unlike the defended spur on the north, the free spur is not a rela- 

 tively permanent feature of the valley ; it will be removed without 

 difficulty if Little river takes a fancy to trim away its western base. 

 Nevertheless, its occurrence to-day does not appear to be altogether a 

 matter of chance, for it seems to illustrate the systematic features 

 described on page 322. 



The main basin is enclosed on the northwest by a well-defended 

 spur, known as Prospect hill, A, Figure 39, just west of Westfield sta- 

 tion • this will be further described with the terraces of the western 

 division of the valley. On the southwest, Little river is held from 

 swinging at present levels by superposition on a transverse sandstone 

 ledge, to which brief reference will be made further on. The contrast 

 between the openness of the main basin, excavated where the streams 

 have not been restrained by ledges, and the narrowness of the entering 

 valleys where ledges have been encountered, is most striking. 



Western Section. The western division of the "Westfield terraces, 

 occupying the valley for about four miles from Westfield village to the 

 base of the hills, is of greater interest than the eastern, inasmuch as it 

 preserves the records of river work at many levels between the highest 

 and the lowest plains. I have prepared a somewhat detailed account of 

 it for publication in the " American Journal of Science," and hence shall 

 here refer only to such features as confirm the deductions of earlier para- 

 graphs. 



The chief features of this interesting locality are shown in bird's eye 

 view in Figure 39, as if looking northeast from a height of several 

 thousand feet above the left front corner of the diagram. The Boston 

 and Albany railroad runs through the view for a distance of about a 

 mile and a half ; the foreground scale is larger than that for the back- 

 ground. Heights are exaggerated. Outcropping ledges are black. 



From Westfield to a small rural settlement known as Pochassic Street, 

 two miles to the west, many small ledges are exposed, and man} 7 step- 

 ping terraces occur along the northern side of the valley. Few ledges 

 are seen on the southern side, and there the valley is generally bordered 

 by a strong upper terrace, with a few low terraces beneath it. On the 



