HOOSAC EIVEE. 125 



with the size of the river, and may have been formed by some currents of water from foreign sources at an 

 early date. We understand that this valley extends to Island Pond, at about the same elevation. If so it 

 may throw some light upon the existence of some former river. 



Upon the west fork of the Passumpsic above Lyndon, deposits of sand and gravel, similar to those at 

 Lyndon, are found along its whole course. Many interesting sections might be taken in the excavations 

 made by the railroad, that would illustrate various phases of stratification, as well as the relations of the 

 different kinds of alluvial deposits to one another. Sections similar to one represented in Fig. 41 are very 

 common, and they may perhaps show that a large part of former deposits of sand and gravel have been 

 worn away. 



Concerning the tributaries of Connecticut River in Essex county, we can say nothing. This region is 

 not traversed by roads, and has not been visited with reference to this point. We should presume, however, 

 that terraces occur on every tributary of considerable size, especially upon Nulhegan Eiver, and the outlet 

 of the two Leach Ponds in Averill and Canaan. Indeed, upon the latter, at its mouth, we saw five or six 

 distinct terraces running up the valley, but could not examine them above the village of Canaan. 



TERRACES IN THE SOUTHWESTERN PART OF VERMONT. 



Deerfield River waters seven towns in Windham and Bennington counties, and empties into the 

 Connecticut in Massachusetts. Its valley is noted for its remarkably fine terraces, in Massachusetts ; but 

 in Vermont the action of drift, and of glacial agency at a recent date, has not facilitated the formation of 

 terraces, because it has filled the valley with very coarse materials, which water has not been able to act 

 upon effectually. Along the Deerfield River in Readsboro, Whitingham and Wilmington, a few small 

 terraces of gravel are frequently seen, and sometimes they form a marked feature, as at Readsboro City. 

 Upon the west branch remnants of high terraces are occasionally seen, and near the summit level of the 

 Green Mountains there is a distinct basin of small size at Hartwellville. There seems to have been a 

 barrier below the village which has been removed comparatively recently, which was an essential element in 

 their production. This plain or meadow is about 1200 feet above the ocean. 



Following up the main stream of Deerfield River to Searsburg, the terraces give place to huge blocks 

 and bowlders of mica schist, which continue to Somerset. Upon the Wilmington branch the terraces are 



I made of gravel, and are of small size ; and scanty numbers of them may be seen as far as West Dover 

 and East Somerset. Yet they are sufficiently large to have fine farms located upon them. 



Passing to Stamford, a few terraces show themselves upon the north branch of Hoosac River, and by 



! the time that we arrive at the south State line, the valley has become quite wide, and contains tertiary 



i deposits of kaolin clay and hematite, below the alluvium. 



We find the same Hoosac River again at Pownal, where it is much larger, and the alluvial accumulations 



j upon its banks much more interesting. In Massachusetts the river passed around Oak Hill in Clarksburg, 



I to Williamstown ; and from there to Vermont, through a very deep valley, and intensely interesting 



geological region. The following facts respecting the surface geology of Hoosac River in Pownal, have 

 been derived from the notes of the Principal of the Survey. 



As soon as the Hoosac River enters Vermont it makes a bend of more than a right angle, within and 

 without which are grouped several terraces. There are five on the north side, and the same number are 

 found, except some local variations, through the whole of Pownal. At this bend they are not all placed in 

 order, but are found near each other. The first terrace on the north side is scarcely six feet above the 

 water, and is not extensive ; the second is 16 feet above the river, or ten feet high, and is more extended 

 than the first ; the third is 20 feet high, or 36 feet above the river. All these are composed of loam and 

 sand. The fourth terrace is 102 feet above the river at its inner edge ; the fifth is 307 feet above the river. 

 The two last are remarkable, not so much for their great height, as for their slope towards the bottom of 

 the valley, and their composition. The slope is from 6 to 10, of which slope the three lower terraces 

 partake somewhat. And the highest terraces are partly composed of consolidated sand and pebbles, at 



[ileast 100 feet thick. The conglomerate consists of pebbles of quartz, micaceous and clay slates, from three 

 to tour inches in diameter, down to coarse sand, (see Nos. 1-92 and 1-93.) 



