Conglomerates with Gneiss, Talcose Schists, &c. 383 
and the mean taken along the railroad from Ludlow to the summit as 
well as from the Plymouth Ponds). But in the central parts they are 
a good deal irregular. It will be seen that all the central portion of the 
mountain is gneiss of the peculiar kind known as the Green mountain 
gneiss. Above this lies, what has been called talcose schist, with which 
snow- upper part of the schist is the conglomerate already 
described, of a character s tke not to bas mistaken t 
end we found several beds of limestone, but none of quartz. Beyond the 
conglomerate, however, and probably lying seilttaably upon it is an | 
enormous development of granular quartz, which seems to have no coun- 
terpart on the east side of the mountain. 
YQ, 
A, B,C, H, D, 5, F. 
In this section a, b, shows the present surface, a being Wallingford, and 
b Plym outh, From A to B we have the taleose conglomerate ; from 
of | 
from C to D, gneiss with several trap dykes at.H, the poi ie level of the 
railroad ; from D to EK, gneiss with talcose schist ‘and at least two beds 0 
limestone, and several thin pe of qua sh age to a conglom- 
erate. This last rock, so distinct and peculiar, forms a good starting point 
for our reasoning. I think no asolot will "doubt that it once mantled 
over the mountain with the subjacent strata as represented in the above 
section. True, we have not found all the subordinate beds ‘of limestone 
and quartz to correspond on the two sides of the mountain. But there is 
a general correspondence. The beds of Vifeutoi especially, may have 
extended originally over the arch of the mountai n, although it is not com- 
mon to find limestone beds as thin as these, with 30 great | a lateral exten- 
sion. As to the beds of quartz, if this be in nearly all cases a rock pro- 
Taking this ess as a fair re Ps aoe of the Green moun- 
tains, several important inferences fo. 
1. Itshows the gneiss of the Green imitans to form a great 
anticlinal fold not a synelinal a as some have supposed. 
his gneiss underlies the taleose schist, the limestone, the quartz 
rock and the conglomerate. 3. All these latter rocks probably 
once —— over the gneiss, though they have mostly disap- 
peared from the eastern side, except the taleose schist. 
Am. Jour. Sc1.—Seconp Series, Vou. XX XI, No, 93.—May, 1861. 
50 
