344 J. B. Perry on the Geology of Vermont. 
as I think when it is understood, to put the question to rest 
forever. 
There are several localities at which the Potsdam Sandstone 
may be observed resting on the Black Slate very nearly as it 
was originally deposited. No single locality gives all the evi- 
dence ; each that I propose to mention furnishes much that is 
important ; while a great many outcrops need to be examined, 
in order that the relations of the rocks may be seen in all their 
bearings. I will now cite in particular the southwest shore of 
Shelburne Bay; also, Lone Rock Point in Burlington, and the 
northwest side of Snake Mountain, in Addison. In some 
places at these localities the upper part of the slate shows that 
denudation took place before the deposition of the overlying 
sandstone, and thus evinces a want of conformity in the order 
of succession, Again, there are many instances serving to 
prove that the slate was unconsolidated at the time the Pots- 
beds were laid down, and that they (and not strata of 
some. other period) were actually deposited upon the slate, 
which now lies beneath them; for the upper layers of the 
slate contain imbedded in themselves numerous fragments of 
the overlying Potsdam. Moreover, the lower portion of the » 
arenaceous deposit is exactly fitted into all the surface cavities 
and depressions of the slate; so exactly fitted as to conform 
with them entirely, as putty conforms with the irregularities 
of the object upon which it is thrown down; a thing whi 
could not have occurred had not the sandstone been laid down 
upon the slates very nearly as we now find them. It thus ap- 
pears, in the clearest manner, that the two formations occupy 
to-day substantially their origi 
main their true relations to each other. And this leads me t0 
underlying slate. In other places, however, owing to the w2- 
equal pressure exerted at different points, and thus to the 1 
equaliti ! = 
always associated with them cerrespondencies in the two 
