114 



TEERACES. 



Vermont side, No. 4, extends north beyond the limits of the thirteenth basin, and becomes the fifth terrace 

 at Newbury. This is caused by an old river bed, which at a curve above Newbury village has made a 

 number of small terraces, insomuch that two unusual terraces are interpolated between the second and 

 fourth. This will be seen to advantage upon a separate map of the surface geology of Newbury (see Plate 

 V, Fig. 2), at which place we were enabled to make more accurate observations than at any other place 

 between Hartford and Waterford. 



It is in the fourteenth basin, which at the village of Newbury is very wide, perhaps wider than at any 

 point below in Vermont, that these terraces are developed. A view of Newbury and vicinity from 

 Mt. Pulaski exhibits much of the geology of the country. While it shows the terraces but imperfectly, 

 considering their remarkable extent and regularity, it will give a good idea of the configuration of a basin of 

 terraces, showing as it does, the great depression prepared by nature, and its successive adornment at lower 

 levels by meadows and terraces ; at a higher level by a sea beach, and still higher by the drift and naked 

 rocks, whose projecting summits present a surface to be acted upon by storms and currents, thus eroding 

 materials for alluvial deposits. 



In examining the terraces at Newbury, we notice, first, an old river bed, continuing in a straight course 

 from the river above the bend, two miles north of the village. It continues south till near the village, 

 when, upon the second terrace, it makes a turn to the east, following the course of the Connecticut and 

 Passumpsic Rivers Railroad to the depot, when it proceeds to the Connecticut along the valley of a small 

 stream. It is at the bend of the old bed that the interpolated terraces are found, being formed at intervals 

 formerly, just as in similar situations they are now produced. North of the village there is a ridge extend- 

 ing a mile and a half to the Connecticut, in a due north and south direction. This at first is rock, and is 

 doubtless underlaid by rock the whole distance. Next we find No. 6, then No. 5. West of this ridge is a 

 valley, through which the old river bed, already mentioned, passed, where are several terraces and another 

 interesting former bed. The village is mostly upon the sixth terrace : a seventh being imperfectly devel- 

 oped to the south. 



Fig. 60 represents a vertical section of the terrace upon which Newbury is built, No. 6. The relations 

 of the sand and clay can be seen clearly at the spot where the railroad has cut through the terrace, and an 



arched bridge prevents the top from falling down. The first ten feet in the 

 descent are composed of sand, which is the only material on the surface in the 

 whole village. Next comes clay, 25 feet thick by estimate, a blue, silicious, 

 more or less indurated clay, such as is common along the whole valley of the 

 Connecticut. Below this, on the section, we have placed 15 feet of sand and 

 gravel, but it reached to an unknown depth, this thickness being used for 

 convenience, that the section might show the composition of the terrace as low 

 as the level of the river. A careless observer might think that the loam on the 

 north side of the railroad (between the depot and the river), in the meadow, 

 ought to have taken the place of the sand and gravel, as it is lower down. But 

 according to our view, as shown on Fig. 39, facts show that the loam is higher 

 up geologically, and therefore, though it may occupy a lower topographical level 

 it does not run under the clay, as may be ascertained by inspection. This sec- 

 tion may also illustrate the relative position of clay and sand, not only in the 

 Connecticut Valley and in Vermont, but all over New England, and perhaps the United States. Clay is 

 found universally lying under sand, and there must have been some general cause for this order, though the 

 overlying sand is often removed, or may not always have been deposited : just as Potsdam sandstone is 

 sometimes wanting between calciferous sand rock and hypozoic rocks. 



The meadow is very large, the windings of the river being through this terrace exclusively. Doubtless 

 former courses through this flat can be easily traced. Upon the east side of the river the terraces are more 

 continuous than in Newbury. The second terrace occurs at intervals and is very small ; the third and 

 fourth are wanting, and the fifth and sixth are very wide and extend north to Wells River, bending with 

 the river about two miles north of Newbury. Fig. 61 represents some curious shapes which the highest 



FIG. 60. 



Sand. 



10ft. 



25ft. 



15ft. -^--^-_^~~~^; 



Vertical Section of Hie 

 flth Terrace at New- 

 bury. 



