384 E. Hitchcock on the Metamorphism of 
get an approximate idea of the amount of erosion from this part 
of the att mountains. We have flattened down the curve 
described by the strata originally, more than perhaps we ought — 
to do, yet it runs almost twice as high as Mansfield mountain, 
which is shown on the section at M, and is the highest point in 
the chain. The erosion at Mt. Holly cannot have been less than 
8000 feet, which is nearly six times as great as the present height 
of the mountain at the summit level of the railroad. 5. We see 
here how the schists and gneiss may be formed out of conglom- " 
erate. This is perhaps the most important inference, and there- 
fore it will be dwelt upon more fully in the sequel. 
e proceed now to draw some inferences from the facts de- 
tailed respecting the Vermont conglomerates, additional to those 
already given. The Vermont localities teach the same lessons 
as those of Rhode Island, but we think they develop other 
conclusions, 
F bre show, we think, that the elongating and flattening 
force in Vermont must have operated most energetically in the 
direction of the dip, whereas in Rhode Island, it was most pow- 
erful in the direction of the strike. In the latter case it was as 
if two men had taken hold of the ends of a plastic mass, and 
pulled it out horizontally; but in Vermont it is as if one had 
stood at the top of a steep hill, and the other at the bottom. 
This is evident from the fact that when we look at the edges of ~ 
the rock laid bare along the line of the dip, we see little more 
than the flattened edges of the pebbles in the form of laminz, 
but if laid bare along the line of strike we see the scattered 
and even lenticular ends of the pebbles, as shown in fi 
already given. The fact however, that the pebbles are lenticu- 
lar on the basset edges of the strata, shows that the whole force 
was not exerted in the direction of the dip. They were a 
deal flattened horizontally, but never so vertically. 
. We think we can get a glimpse in Vermont of the mode in 
which the force acted to elongate and flatten the pebbles. We 
refer to the bowlder shown in fig. 8, where it is obvious that the 
bending of the rock, if it was plastic could produce that effect, 
scause the outer portions must be extended over wider and 
wider spaces. Hence, as in the figure, a pebble on the interior 
part, might be only moderately extended while the outer ones 
were stretched almost into mere laminz. 
_ Apply now this principle to fig. 10, which shows the manner 
in which, as we suppose, the strata were folded over the top © 
the Green mountains. The effect would be to stretch them out 
more in the direction of the curve, or dip, than at right angles to 
_ it; although the strain would spread them in that direction also, 
to some extent, and it may be that the irregularities that must 
have aceompanied such great movements as the folding up of 4 
