J. D. Dana— Origin of the Rocks of the Cortlandt Series. 107 
the like.conformable association of quartzyte, slate and semi- 
crystalline limestone in the Peekskill region, together with their 
Peexsx 
YP 
Map of part of Western Cortlandt, showing the Peekskill, Verplanck, Tom 
Cove, and Cruger limestone areas, by horizontal lin 
pkins 
ing. Scale, 1 inch to a mile. 
unconformability to the Archean, and their relation to New 
ersey limestones have been adduced, in my former paper, as 
proof of a like Lower Silurian age for the Peekskill beds. 
