Chapter 4 
PET OZOUG tls ORY, 
CAMBRIC PERIOD 
In the preceding chapter we have seen that after the first known 
great Adirondack uplift the whole region, including the district of 
the Highlands-of-the-Hudson, was profoundly affected by erosion, 
and that this erosion began before the Paleozoic age and extended 
well into the early part of that era. Now the question may be fairly 
asked, What became of the sediments which were derived from the 
wearing down of the land during that vast length of time? 
We must admit that, in our present state of knowledge, we can not 
be certain as to what became of the Prepaleozoic sediments. They 
may have washed westward or southwestward into waters which 
might possibly have existed there; or they may have been carried 
northward or northwestward into Canada to help build up late Pre- 
cambric deposits there; or they may have moved eastward toward 
or into the Atlantic basin. The question of the disposition of the 
early Paleozoic sediments, however, can be much more satisfactorily 
answered. Early and Middle Cambric deposits are extensively de- 
veloped in the New England states and along the eastern border of 
New York State, including the Hudson Highlands region. Thus 
we have positive proof for the presence of the early and Mid- 
dle Cambric sea over this region, and it is equally evident that much 
of this sediment which deposited in the sea was derived from the 
adjacent land masses in northern and eastern New York. 
It was not until the opening of the Upper Cambric (Potsdam 
time) that any considerable portion of New York State was 
occupied by Paleozoic sea water. The fact that all the Cambric 
strata, including Lower, Middle, and Upper, are present in the New 
England country and along the eastern border of New York, while 
only the Upper Cambric is present in northern New York, clearly 
shows that the Cambric sea encroached upon the State from the 
east toward the west. To be more exact, it was probably from the 
northeast, because the greatest thickness of Upper Cambric strata 
is in Clinton county along the northeastern side of the Adirondacks. 
The first deposit to form in the Cambric sea of northern New 
York was the Potsdam sandstone and the presence of this forma- 
tion in the St Lawrence, Champlain, and lower Mohawk valleys 
[41] 
