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Niagara
Issues - Devil's Hole http://www.mobot.org/plantscience/ResBot/niag/ |
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Niagara
Issues - Devil's Hole Devil's Hole is a
circular feature in the face of the wall of the gorge of the Niagara River
and is part of the New York State Department of Parks, Recreation and
Historic Preservation. The following are pictures taken in early March, 2003.
The cove is a seepage or groundwater feature. Historically, as the masonry in
the southern wall shows, a stream had its outflow in this cove and is usually
referred to as Bloody Run. This stream has been blocked and the masonry
outlet walled up. Some seepage still occurs in the cove, which appears to be
rather dry. In this picture the stratified caprock may be seen above the
forested talus slope. The large buildings in the distance form Niagara
University, the one-story, flat building on the left is the Power Vista of
the New York Power Authority.
Looking down into the
cove from the top of the stone steps (lower right) which are covered,
together with the ledges, with an evergreen bryophyte (moss) plant community.
The circularity of the cove walls can be seen here. Stream erosion generally
produces a v-shaped channel. Erosion in the cove appears to derive from
'frost-chipping' or sapping. The bedrock disintegrates in vertical plates,
moisture settling between the plate and its bedrock. Calcareous strata
throughout the gorge often show an undulating surface of erosion. There is a
similar feature, a 'Little Devil's Hole' forming in the gorge just upstream
from the northern terminus of the gorge at Artpark (Lewiston, New York), best
seen from the upper railroad hiking path there.
On the gorge rim, just
beyond the lovely old stone masonry wall that marks the edge of the viewing
platform at Devil's Hole overlook on the south boundary of the cove on the
flat tableland above, occur Juniper trees, Juniperus virginiana, which
are evergreen as is the White Cedar, or Arbor Vitae (Thuja occidentalis).
The former has needle-shaped leaves, the latter scaly ones. In the distance
is Ontario and the table-land cut through by the gorge of the Niagara River.
The horizontal feature is the access road to the Adam Beck power generating
plant operated by Ontario Hydro.
This view is the south wall
of the cove at Devil's Hole showing the viewing platform: an area of caprock
covered with a thin lawn and a modest alvar vegetation. The viewing area is
surrounded by a distinctive stone wall. Masonry defining the old "Bloody
Run" stream outlet is visible here. No seepage occurs here. Down on the
talus below that fills the cove-ravine a stream emerges out of the rubble and
wends its course down to the base of the cove into the river below. This
stream or seepage may be related to the blocked up stream that once cascaded
into the cove, and which contributed to a higher moisture regime there than
exists today. Calcareous substrates and rubble and well known to produce
desiccation stress on plant communities. Loss of moisture from this outlet
would contribute to more of an arid situation than what existed historically,
with pressures on bryophyte and pteridophyte communities that lined the rock
substrates. Note the rounded terrace of loose sediment that faces the flat
viewing area on the left.
On the north wall of the
cove some seepage is displayed from the upper strata, but on the whole, the
cove does not display much frozen moisture. Moisture here appears to be more
cryptic, infiltrating behind rock surfaces. The stone steps leading down to
the river in the middle of the talus-ravine are visible here.
From the viewing
platform above, on the south boundary of the cove may be seen an extensive
exposure of rocky river bed extending out into the stream flow. This area is
denuded of vegetation as yet, and it appears to be covered with water during
the growing season. The riparian bank of the Ontario shore is visible, and
the Ontario Hydro access road.
Looking upstream over
the masonry wall on the viewing platform at Devil's Hole, the Niagara Glen
forest in Ontario may be seen without its summer canopy of leaves.
More of the Niagara Glen
terrace at the base of the gorge and the area of exposed riverbed at its
downstream boundary, similar to the exposed bed where the Devil's Hole cove
meets the Niagara River shown above.
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