J. B. Perry on the Geology of Vermont. 345 
showing that the lateral motion was one of small extent. From 
these facts, to mention no others, it is evident—(1) That the 
two series of beds are unconformable ; (2) That the sandstone 
was deposited, nearly as it is now found lying, upon the slate ; 
(8) That, in some places, there has been no horizontal move- 
ment of the rocks upon each other ; and (4) That there has 
| been, in other localities, a slight, and only a slight, sliding of 
| the upper mass upon the lower. We thus see that the under- 
| éVying black, argillaceous beds cannot, by any possibility, be 
| Utica Slate, or Lorrain Shales, * 
: But let us look at another phase of the matter, Some have 
Supposed that the sandstone, while it overlies the Swanton 
Slate, runs under the beds of the Georgia Group, which, in 
| Stance of its underlying, or running beneath, the beds of the, 
| Georgia Group. ee 
This, however, is not all the evidence. An outstanding bed 
| of what appears to be Potsdam Sandstone occurs as an over- 
| lying mass near Franklin Centre, and not far from the eastern 
} limits of the Brown Slate. But a still better view of these 
| Tocks, and one respecting which there seems to be no question, 
_ May be secured in the counties of Chittenden and Addison. I 
_ Tefer to the fact that the Potsdam Sandstone extends in these 
Counties broadly to the east. In order to observe this exten- 
7 «Sve exhibition of the rock, one may start from a point in 
a Charlotte, on the west of the Red Sandstone, and where it 
tes on the west, extending across the entire limits of the 
porgia Group, and also rate a portion of the Lower 
Taconic beds. He may, accordingly, observe reposing uncon- 
formably beneath the Potsdam Sandstone, a series of forma- 
|. That portions of the Utica and Lorrain formations may occur in the. same 
teighbortood with, the Petia Sandstone, is, of course, possible, and most 
freely itted. : 
: Ax, Jour. Sct.- -SECOND SERIES, Vou. XLVII, No. 141.—May, 1869. 
23 : 
