J. B. Perry on the Geology of Vermont. 341 
Ant. XXX.—A Point in the Geology of Western Vermont ; 
by the Rev. J. B. Perry. 
main sections. Starting from the west we have, first, the 
Black Slates, or the Swanton Group, which includes thin beds 
of sandstone and limestone. Proceeding eastward, in appa- 
rently ascending order, we encounter the Brown Slates, or the 
Georgia Group, which also contains thin beds of interstratified 
sandstone and limestone, and is capped on the east by a con- 
glomerate. Along the western portion of this series there is a 
- band of Red Sandstone running northerly and southerly which 
has come during the past few years to be regarded with cer- 
tainty as of Potsdam age. 
Now, these formations, according to a view which has been 
Very widely prevalent, are made up of Lower Silurian rocks, 
Which have been largely affected by heat, their structure 
having been more or less effaced, and their organic remains 
either obliterated, or, to a considerable extent, obscured. We 
, accordingly, invited to look at the formations in question, 
for a few moments, that we may see how far this theory is 
Sustained by facts. 
