20. Jenny Jump State Park
The Jenny Jump Mountains were named after a colonial girl who allegedly
followed her father's suggestion to jump of a cliff to avoid being ravaged
by stalking Indians. That jump proved to be fatal. Today part of the mountainous
area is preserved as wooded parkland of Jenny Jump State Park.
Extending northeast through park is a high ridge with exposures of foliated
gneiss along its crest. The rock along the western side of the ridge and
in many patches along the ridgetop are barren of topsoil. This is an indication
that the Wisconsin ice sheet overran the hilltops in this region, even
though the southernmost terminal moraine of the Wisconsin glacier is located
only a couple miles to the south. The ice at Jenny Jump must have been
well over 1,000 feet thick. The rolling topography in the valley between
Hope and the park are terminal and recessional moraines which accumulated
as the continental glacier haltingly melted and re-advanced before completely
vanishing from the region about 20,000 years ago.
The Summit Trail which leads to two overlooks is a gentle climb that
is less than a quarter of a mile. The two prominent lookout areas are
well worth the walk. They offer an open west-facing view for nearly twenty
miles across the Great Valley to the high ridge of Kittatinny Mountain
and the Delaware Water Gap. The first overlook closer to the trailhead
parking area is an open, rugged patch of layered hornblende granite gneiss
(Figure 46). The barren exposures are fringed with pitch pines attempting
to establish a hold on the barren rock. A few hundred meters beyond the
first overlook is a second barren patch of gneiss bedrock that provides
a better view of the Great Valley. Near this second vista point is a collection
of large glacial erratics. Most consist of local gneiss, but one consists
of hard, banded quartzite, probably Cambrian Hardyston Sandstone (Figure
47). This large boulder is elevated on smaller blocks, and is reminiscent
of Tripod Rock on Pyramid Mountain, only on a smaller scale.
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Figure 46. A glacier-scoured, layered gneiss outcrop in Jenny Jump
State Park provides a westward view across the Great Valley to Kittatinny
Mountain in the distance. |
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Figure 47. A pedestal glacial erratic of Cambrian Hardyston Sandstone
resting on Precambrian gneiss on the ridge top at Jenny Jump State
Park. |
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