Rivers,
and on the west into the Hudson River. The Hudson River thus becomes a
very old, a pre-Silurian, river cutting its way to the ocean in a
gorge, perhaps accentuated by falls and rapids, with probably equally
picturesque tributaries.
Borings
made by the Board of Water Supply of New York City, in connection with
the project of bringing water from the Catskill Mountains, have shown
the existence of numerous deeply buried channels representing
pre-glacial stream courses. Many of them indicate channels cut far
below present sea-level at considerable distances back from the Hudson
River. From engineering records it appears that the depth to bed rock
in the Hudson River has never been determined at any point in its lower
course. Profiles of supposed rock-bottom based upon wash-borings have
been proven by the recent work to represent simply the bottom of the
finer silt filling. The results show that more than 200 feet of more
compact material lies below this silt at the point now being tested,
and that the rock bottom of the ancient Hudson lies more than 450 feet
below the present river level throughout a large part of its lower
course. (C. P. Berkey.)
This
assumption involves, of course, a much higher elevation of the whole
coast. As far as the Hudson River is concerned, the next problem it
presents is its historical relation to the Triassic beds west of it in New Jersey (Newark formation) and the Palisade escarpment. Geologists agree that the Palisade dike is intrusive, ins., was
inserted in overlying beds of sediments, and we must assume a
depression for their accumulation in the brackish water (Eastman)
trough or basins of the Triassic deposits, which depression, however, did not submerge
the meridional ridges of Manhattan Island and western Connecticut.
Again, elevation supervened, and at this point it seems necessary to
intercalate a fault line, perhaps, on the west margin of the Hudson
River channel to give differential prominence to the Triassic shales,
sandstone, and
