55. Crosswicks Creek
The Early Paleocene Hornerstown Formation crops out along the streams
and lower hillsides along Crosswicks Creek east of New Egypt, New Jersey.
In the past this area was intensely studied for its paleontological resources.
Fossils are generally scarce in this dark green glauconitic sand formation
with the exception of rare molds and casts of gastropods, pelecypods,
and bone material. The overlying Paleocene Vincentown Formation crops
out on the hillsides and along tributaries of Crosswicks Creek. The Vincentown
is recognizable by an abundance of the brachiopod, Oleneothyris harlani,
and an occasional oyster, Gryphaea dissimilaris; other fossils
are scarce (Figure 132, and see descriptions of the Vincentown and Hornerstown
formations on the Tertiary Stratigraphy page). These fossils occur in massive pod-like lenses with individual
shells embedded chaotically in a glauconitic marl matrix. The occurrence
of such a great abundance of brachiopods is very unusual after the close
of the Paleozoic. The general lack of other types of fossils suggests
that the brachiopods were either well-adapted to a specific range of conditions
in a shallow marine setting, or possibly, they had very little competition
from other species following the mass extinction at the end of the Cretaceous.
|Figure 132. An Oleneothyrus shell bed in the Vincentown Formation
near New Egypt, New Jersey.
The state has recently made parking and public access to the stream for
fishing and canoeing. A parking area is located on Route 539 just south
of the intersection with Route 537 near Hornerstown (just east of New
Egypt, New Jersey). From this location it is possible to walk or wade
downstream to examine cut banks along the stream and along side creeks;
there is no trail, and conditions can be downright miserable during mosquito
season. Like all major streams in New Jersey, the main channel is accessible
to the public, but cut banks along the side of the stream may be private
land. If signs are posted, then the banks are off limits without the land
owners permission. Fossils can occasionally be found on gravel deposits
when stream levels are low. Be aware that Crosswicks Creek is extremely
hazardous during high water, which means practically any time of year,
but particularly in the late winter to late spring.