DAVIS : KIVER TERRACES IN NEW ENGLAND. 333 



upon previously buried spurs. Brown's spur is peculiar hi being closely 

 trimmed on the down-valley side as well as on the up-valley side. 

 Prospect spur has a terraced re-entrant, C, scoured out at mid-height 

 with small radius and large arc, far back on its up-valley side ; that is, 

 a meander of the river has there been twice compressed against defend- 

 ing ledges, after the style of Figure 30. Elsewhere the meanders 

 seem to have slipped past the defending ledges, after the style of 

 Figures 25 to 28. 



The terraces on the south side of the valley are in several cases de- 

 termined indirectly by the ledges on the north side. This is most 

 distinctly the case where "the river formerly swept forward from the 

 lowest and furthest forward of the Pochassic ledges, M, and consequently 

 cut out one of the deepest re-entrants on the south side of the valley, P. 

 A single scarp now descends from the high-level plain into this strong 

 recess. Similar but less manifest relations are suspected elsewhere ; 

 thus K', K", K " on the north may correspond with S', S", S'" on the 

 south. Conversely, a number of low-level terraces remain on the south 

 side of the valley south of Brown's spur, perhaps because the repeated 

 northward swings of the river into the largest northward re-entrant, 

 that between Brown's and Prospect spurs, have not required their 

 removal. The numerous free cusps here found exhibit the features al- 

 ready deduced as of common occurrence. It is intended to make 

 a close measurement of the slopes of these terrace plains in the hope of 

 correlating the now separate remnants of single flood plains, and thus 

 tracing the history of the terracing process in some detail. 



Little River. A few words may be said about Little river, although 

 the southern side of its valley has not been closely studied. The valley 

 of this stream is divided into three sections by two barriers of sandstone, 

 next up-stream from which are considerable bodies of till. The till has 

 been cut down to grade with the sandstone barriers, but the valley in 

 the till is held to a small width, practically without terraces. Relatively 

 few terraces are found even where the valley is bordered by stratified 

 drift. In explanation of this it should be noted that Little river is 

 smaller than the Westfield, and that a small stream must be hurried in 

 attempting to keep pace with the degrading action of its master. Hence 

 the smaller stream will have little opportunity for lateral swinging and 

 terracing so long as it runs through loose drift to a more actively degrad- 

 ing master stream. There are two conditions under which opportunity 

 for lateral swinging will be presented to the smaller stream. First, when 

 the master stream has effectively ceased degrading its valley. This is 



