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| Rock Run's valley is truly a
fascinating place and one of the most popular destinations in
Bernheim's Research Forest. The geologic story of Bernheim
more so than anywhere else in the forest is best represented here.
From the lowest part of the creek bed to the top of the knob this
390 foot deep entrenched valley contains 6 different rock
formations representing 3 geologic periods of
time. |
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Laurel Dolomite is found at the lowest level in
Rock Run Creek followed by Waldron Shale then the Louisville
Limestone. All 3 are from the Silurian geologic period which means
they were formed over 325 million years
ago. The Louisville Limestone
rises from the creek bed to about 25 feet above the creek along the
trail. Beechwood Limestone is located between 25 to 35
feet above the creek bed and the New Albany Shale is located from
about 35 to 100 feet above the creek. These two formations
represent the Devonian period from 280 to 325 million years ago.
From about 100 feet
above the creek bed to the top of the knob is the New Providence
formation. This is the
youngest rock formation from the Mississippian period having been
formed between 250 to 280 million years
ago. The New
Providence formation is composed of several different members that
contain shale, siltstone, soapstone, ironstone, limestone, and
geodes. Fossils can be
found in the New Providence formation, Beechwood Limestone, and
Louisville Limestone.
The most common fossils found in the Rock Run area are crinoids,
brachiopods, and corals.
This Earthcache requires hiking the short Rock
Run Loop trail, answering questions about information contained in
the trail log and about what you observed along the
way. |
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Parking – N37.54.736 W085
38.885
Parking is located right next to Rock Run and directly across the
street from the Rock Run trailhead. |
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Trailhead
- N37 54.742 W085
38.873
Rock Run Trail is a 1/2 mile loop trail that will require some
climbing of steps with an uneven and an
 occasional steeply slanted
surface. The hike is
recommended for children but please monitor their activities
especially near a few, sheer drop offs along the trail.
There is an
interesting and informative sign marking the beginning of Rock Run
Trail. Please
take few moments to look over this
sign. Once you begin
your hike you will want to stay to the right when the trail splits
and follow the red triangle markings on the trees.
The land where you are now standing was created more than 250
million years ago when a shallow ocean covered the entire
area. Over great
periods of time mud, silt, sand, and sea creature remains settled
to the bottom building layer upon
layer. When the oceans
receded those sediments hardened creating the limestone, shale and
siltstones around and beneath
you. As rock far
beneath the surface shifted and pushed against each other this
caused a slow folding and uplift of the ground which created the
Knobs that surround Bernheim.
Long periods of erosion followed that reduced the
height of the surrounding hills and created Bernheim’s
valleys. |
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Rock Run Creek View - N37 54.797 W085
38.851
A common reaction from visitors to Rock Run is where is all the
water? This is true
especially if they visit during periods of sparse
rainfall. The answer
to this lies in the extensive karst activity in the
valley. Karst
topography is a landscape that is shaped by dissolution of layers
of solid bedrock. Here
the soluble bedrock is Louisville Limestone and Laurel
Dolomite. When water
flows down the creek and reaches cracks in the limestone it will
sink and then travel underground leaving little to no surface water
flow. Over time the
water flowing through the cracks and crevices will dissolve more
limestone and create even larger subterranean drainage
conduits. Only during
heavier water flow periods will those subterranean channels fill up
and force water to once again flow down the surface of the creek
bed. This area is
marked by numerous sinking streams, resurgences, and
springs. |
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Dry Streambed - N37 54.812 W085
38.843
The side stream to the right of the trail is typical of an
ephemeral tributary stream found in the
area. This V-shaped,
steep sided ravine represents an early stage of valley
development. Water
flowing down a small channel over time has eroded the surrounding
sediments, carrying them downstream and creating this
ravine. Over a long
geologic period of time this water movement and erosion causes the
ravine to widen and the streambed to entrench deeper creating a
valley like Rock Run.
The wide flat valley found at the entrance to Bernheim Forest
represents an even more mature stage of valley development.
At this point the side stream crosses the trail and drops 6 feet
before tumbling into Rock
Run. During periods of
heavy rainfall there is a nice little waterfall just below where
you are standing.
Anastamosis Channeling - N37 54.843 W085
38.844
At one time in an earlier stage of Rock Run's valley development
the area where you are standing was under
water. As groundwater
slowly moved through crevices in the nearby rocks, weak carbonic
acid in the water slowly dissolved the surrounding
limestone. Some areas
of limestone were less susceptible to dissolving than others. The
result of this action is what you see before
you. It’s actually a
remnant of an old cave system where the softer limestone was
dissolved and washed away leaving the channel matrix you see
today. Eventually, the drainage waters of Rock Run Creek
would entrench down even further and over time erosional processes
exposed these large rocks. |
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Cliffs, Waterfalls, and
Spring - N37 54.906 W085 38.831
 Spend a few minutes here. Sit on the memorial bench
and enjoy your surroundings. Across the creek is a cliff line
with multiple rock shelters, two waterfalls, and a spring. Of
course, most of the time the waterfalls do not actually have a flow
but if you are fortunate enough to be here at the right time you
can see the spring and waterfalls in action. In the winter
icicles can make for an enchanting display along the cliff line in
this area.
If it has rained recently and you look directly across Rock Run
from where you are sitting, you will see a small, ephemeral spring
located about 25 feet above the
creek. It emerges from
a 3 inch bedding plane located directly under an 8 foot high by 8
foot deep rock shelter. Rock Shelters like these are
developed when a more resistant rock sits on top of a softer rock
that is susceptible to erosion and
weathering. The softer
rock is eroded away leaving an alcove. |
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Side Stream - N37 54.926 W085
38.812
During or shortly after rainy periods, water in the side stream to
the right sinks just below a 10 foot high cascade that can be seen
about 175 feet upstream from
here. The water then
flows about 100 feet underground and reappears as a small spring
that issues over a 3 foot
high waterfall. It’s
very interesting to see this as it demonstrates on a small scale
the karst activity that is currently taking place in this
valley. |
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 Rock
Run Creek Crossing - N37
54.930 W085
38.800
Rock run Creek from this point flows both above and below ground
until it deposits into Long Lick Creek about 1/2 mile from
here. The creek
bed of Rock Run has many small vertical cracks called fissures and
horizontal cracks called bedding planes that lie below
it. Water will always
take the path of least resistance and will seep through these
cracks when possible.
During periods of drought or low water flow, most of Rock Run's
drainage will be unseen below the creek
surface. During
periods of rain the fissures and bedding planes become full and
water will then flow above ground down the creek
bed. During normal
weather conditions all water flow in Rock Run sinks about 950 feet
downstream from here when the water reaches the Louisville
Limestone and Laurel Dolomite contact.
The trail at this point crosses Rock Run and steeply ascends above
the cliff line for a return hike back to the parking lot. The
first part of the return trail offers scenic views of the creek
from above the cliffs.
Waterfall and Rock Shelter - N37 54.908 W085 38.841
The trail at this point crosses over one of the waterfalls and
rock shelters you observed from the other side of the creek.
Once you cross the small side creek and look back you can better
view the cross section of the rock shelter. |
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Stair Step Dry Cascade
Waterfall - N37 54.871 W085 38.842
 Unfortunately, you would have to be here during a
rain storm to see this cascade waterfall in
action. Most of the
year it just appears as an interesting stair stepped Louisville
Limestone landscape feature dropping down into Rock Run
Creek. Near the base of this waterfall is a seep. Even
during some of the driest conditions water slowly seeps out of the
ground here and quickly disappears into the cracks in the bottom of
the creek. This is called an occluded spring.
 Rock Run Creek Crossing -
N37 54.803 W085 38.861
The Trail crosses back over Rock Run at this
point. Spend some time
here and observe the different type of rocks in the creek
bed. Many were washed
down stream during rapid water movement in the
creek. If you look
closely you can find fossils located in the exposed Louisville
Limestone and the loose rocks lying in the creek
bed. You can also find
rocks here that contain embedded calcite
crystals.
The trail
from this point ascends from Rock Run and returns you to the
parking lot. If you
have some extra time visit the eroded limestone creek bed next to
the parking lot which contains some interesting rock
formations. |
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To get credit for this
Earthcache post a picture of yourself with GPS in hand of your
favorite spot along Rock Run Creek, and send an email to
Mooseky@gmail.com with the
answers to the following questions .
Questions:
1. About how old is the oldest rock found in Rock Run
Creek?
2. Name one kind of fossil that can be found in Rock Run?
3. What is a landscape called that is marked by soluble
bedrock that has been partially dissolved and removed by water?
4. What are the approximate dimensions of the largest
anastamosis channeling you found along Rock Run?
5. What is the approximate width of Rock Run at the first
crossing?
6. How far does the dry Stair Step Cascade drop from the
trail down into the creek?
Please use
caution when in the area, the trail and the rocks in the creek can
be
slippery.
Remember Bernheim
Forest is a
sanctuary.
No removal of natural resources such as plants, flowers, rocks, and
fossils is allowed.
References:
The Geology Of Bernheim Forest by Ruth G. Browne – 1958.
The Geologic Story Of Bernheim Forest by Preston McGrain -
1967.
Caves and Karst of Kentucky by Donald C. Haney - 1985.
Geologic Map Of The Shepherdsville Quadrange, Bullitt County KY.
by Roy C. Kepferle - 1968. |
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For more information about
Bernheim Arboretum And Research
Forest including current operating hours. There is no admission
fee at Bernheim on Monday through Friday. On Saturday &
Sunday there is a $5 fee per passenger car, mini van, or
motorcycle. |