256 J. D. Dana on the Green Mountain Quaritziie. 
initial step in the making of these mountains, and the position 
of which modified the action of the causes depositing later beds, 
and also, by their unyielding nature or resistance, the action of 
forces uplifting them. | 
at, evther the quartzite was a ledge within or along the 
shores of the sea in which the limestone was deposited, the 
two being unconformable and no intermediate beds being pres- 
ént; or elsethere is a fauit between the quartzite and limestone, 
along which the Archean rocks (overlaid by the quartzite) were 
brought up to their present position so as to be on a level with 
the limestone beds. 
The latter view is favored by the fact that the line of this 
supposed fault nearly accords with that to the north between 
the limestone and Taconic gneiss. The former view is support 
by the facts that (1) the Taconic slates, schist or gneiss, which 
ought to have been carried up on top of the Archean rocks 
and quartzite, in case of such a fault or uplift on its east side, 
nowhere exist in the vicinity of Poughquag, and are not known 
_ It isa remarkable fact that in this Poughquag region no beds 
intervene between the Archzan and the quartzite, although 
some pre-Silurian strata might reasonably be looked for, and 
none between the quartzite and the limestone, although so great 
a thickness of strata really exists in the vicinity inferior to the 
limestone. 
are 
