90 SURFACE GEOLOGY. 



so perfect upon a small hill. This fact goes strongly to show that at least a large 

 part of the Deerfield basin was once filled with terrace materials, which the river 

 has subsequently worn away, and the reason why those on Pine Hill remain, I 

 find to be that they rest on a protuberant mass of red sandstone. On the west 

 side of the hill, as shown in the section, is an ancient bed of Deerfield river (crossed 

 twice by the section), which was prevented from making any further lateral encroach- 

 ments by the underlying rock. I shall have more to say hereafter concerning the 

 ancient beds of Deerfield river, shown in such numbers upon Map No. 2 (Plate IV). 

 A few other terraces on Deerfield river, out of the Connecticut valley, will be 

 noticed further on. 



The Westfield Basin. 



17. The major axis of the Deerfield basin lies north and south; that of the 

 Westfield basin nearly east and west. The present section starts from Agawam 

 river, near the east end of the basin, on the north side, and runs northerly. The 

 height of the four lower terraces was obtained by levelling ; that of the highest by 

 estimation. All of them, except the lowest, which is loam, are sandy. The most 

 elevated brings us to the general level of the Connecticut valley, though it is for 

 the most part lower towards the east side, and not a little irregular on its top. 



18. This section was but imperfectly measured, and only with the arenoid 

 barometer; which, although very valuable where an error of twenty or thirty feet 

 is not of much consequence, does not answer well for such small elevations as our 

 river terraces. By looking at Map No. 6, it will be seen that between Westfield 

 river and Little river, a tongue of terraces extends easterly from Middle Tekoa 

 Mountain, almost to the village of Westfield. In one place on the north side of 

 this tongue, perhaps a mile west of the village, I noticed five terraces, reckoning 

 that on which the village stands as the lowest, although generally the highest 

 terrace around Westfield is reached by three steps from the river. Commencing 

 on the high sandy plain north of Westfield basin, I have carried this section 

 southwesterly across these five terraces and over Little river to the plain of nearly 

 equal height on its south bank ; in other words, across the entire basin. I think 

 the barometer has made the central terraces considerably too high. But the sec- 

 tion will give an idea of this interesting valley. The materials of which all these 

 terraces are formed are clay, sand, and gravel, though the red sandstone shows 

 itself occasionally near the river. 



19. On this section I have attempted to give an idea of what I suppose to be 

 the remnants of gorge terraces, where Westfield river issues through the deep 

 gorge between Tekoa and Middle Tekoa. The height (measured by the Aneroid), 

 is very great for a stream of no larger size. Near the river on the same section 

 are shown two other narrow terraces, produced at a vastly later period. On both 

 sides of the river the mica slate ledges show themselves frequently as we ascend 

 the mountains. 



20. This section commences on the east side of Westfield river, opposite the 

 station house of the Western Railroad, in Russell, and crosses the river, passing 

 westerly through the flourishing village which has lately sprung up there. Its 



