51. Atlantic Highlands
The Atlantic Highlands are the highest headlands along the Atlantic
Coast south of Maine. On a clear day they can be seen from the southern
shoreline from most of Queens, Brooklyn, and especially Staten Island.
The view of the Atlantic Highlands escarpment from the Raritan River Bridge
on the southbound Garden State Parkway is particularly impressive. However,
perhaps the best view of the Highlands is from the bay side of Sandy Hook.
The views from the top of the Atlantic Highlands are equally spectacular.
Just off NJ Route 36 in Highlands, New Jersey is the Mt. Mitchell Overlook
that offers a wide view including the Manhattan skyline, Staten Island,
Brooklyn, and Sandy Hook. An equally impressive view is from the top of
the north tower of the Twin Lights Museum on the hilltop just south and
east of the Navesink River Bridge on Route 36.
The amazing height of the Atlantic Highlands may best be attributed to
the effects of glacial rebound; whether other basement faults are involved
is unclear. Resistant Tertiary-aged ironstone conglomerate forms a caprock
along the crest of the Atlantic Highlands, overlying gently seaward-dipping
Cretaceous marine mudrocks. A large abandoned sand pit in the Cohansey
Formation is visible along the south side of Route 36 near the hill top
west of Navesink, New Jersey (Figure 126). When sea level was lower during
the Pleistocene, the Atlantic Highlands was a high valley wall on the
south side of the combined Hudson/Raritan Rivers. This river system has
since been buried by younger sediments including the recent deposits associated
with Sandy Hook Spit. The Beacon Hill Gravel (Pliocene?) is fairly well
exposed at the base of the water tower in Highlands (just west of the
Mt. Mitchell Overlook [Figure 127]). It is particularly interesting to
compare this deposit to the modern gravel deposits on Sandy Hook. They
are essentially the same!
|Figure 126. Map of the Atlantic Highlands area overlooking Sandy
Hook and the Navesink River estuary in Monmouth County, New Jersey
(including Hartshorne Woods Park and the Mt Mitchell Overlook).
|Figure 127. Gravel outcrop of the Beacon Hill Gravel (Pliocene)
of the Cohansey Formation near the water tower in Highlands, New Jersey
(near the Mt. Mitchell Overlook, Monmouth County).
The underlying Cohansey Sand (Miocene) weathers to form the brown sandy
soil throughout the hilltops in the area. Both units can be appreciated
by walking through Hartshorne Woods Park in Highlands, New Jersey. This
preserve is host to a mixed oak, hickory, beech, maple forest. The upland
area is host to a thick understory of mountain laurel, holly, and blueberry
that thrive in the acid soil developed on the Tertiary sand and gravel.
Chunks of limonite-cemented gravel (bog iron) are common along the trail.
This park is particularly scenic when the mountain laurel blooms in late
May to early June. A cool morning walk through Hartshorne Woods before
a trip to the beaches at Sandy Hook is particularly enjoyable!