Davis — Terraces of the Westfield River^ Mass. 79 



north side of the valley near Westiield railroad station, thence 

 going west about two miles to a little settlement known as 

 Pochassic Street ; and returning bj the south side of the valley 

 to the village again. The general j)attern of the terraces is 

 indicated in figure 6 (Plate lY), where the attempt is made to 

 show them in bird's-eye view, as if looking northeast from a 

 height of two or three thousand feet above a point about a mile 

 south of Pochassic Street. The scale in the further part of the 

 view is somewhat smaller than in the foreground. The vertical 

 scale is significantly exaggerated. The Boston and Albany rail- 

 road is not so straight as it is here drawn through the valley ; 

 about a mile and a half of its length is shown. Defending 

 ledges are drawn in black. Poads are dotted. 



3. The open Westfield plain. — Just north of Westfield 

 station, a good view is had from the terrace near Prospect hill 

 schoolhouse, A, figure 6, over a broad plain that the river has 

 excavated east of the village. The plain is limited on the 

 north by a single high terrace, B, rising at once from the 

 marshy abandoned river channels at its base to the level of 

 the highest drift plain of the district. On the opposite side 

 the flood plain of the Westfield is conflueut with that of (West- 

 field) Little river (not shown in fig. 6), limited on the south by a 

 single high terrace, to-day undercut by Little river at tw^o 

 places. The low plain thus gains the unusual breadth of a 

 mile or more for a distance of about two miles eastward from 

 our j)oint of view. The two rivers here show no incompetence 

 whatever in the process of lateral swinging. Whatever loss 

 of volume they may have suffered — and some loss since the 

 disappearance of the ice sheet is highly probable — and how- 

 ever recent the last uplift of the region may have been, these 

 two streams are here sweeping over a broader valley floor 

 to-day than they have opened at any earlier time ; for whatever 

 earlier flood plains they have formed at intern\ediate levels, 

 during the process of excavating their valleys, are now com- 

 pletely undercut and destroyed (except for a few low terraces) 

 by the opening of the present broad plain. The prime reason 

 for so striking an exhibition of competence on the part of the 

 streams is believed to be the absence of rock ledges in this 

 section of the valley. ]^o ledges have here been discovered 

 by the degrading streams ; their high terrace scarps consist of 

 clays, sands and gravels (the latter near the top), very easily 

 eroded wherever the streams flow against their base, as may 

 be seen where Little river is now swinging against the terrace 

 scarp on the southern side of the plain. A secondary reason 

 for the competence of the river to swing so broadly at the 

 present level is probably to be found in the delay of further 

 valley-deepening and in the resulting detention of the streams 



