Greenville Natural Arch EarthCache
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The Earthcache is located in a State Scenic River Area and is maintained by the Miami County Park District.The Park hours are 8 A.M. to Sunset daily. Terrain is rated 2.5 because of a steep incline down to the site.
This is in the Greenville Falls State Scenic River Area. Be sure to also see the Falls from various lookout points.
Note: Recommended Parking is at the waypoint: N 40° 06.340 and W 084° 22.418
Recommended viewing is at: N 40° 06.470 and W 084° 22.437
Be sure to stop and look at the various historical man-made structures that are still exist on the way to the recommended viewing coordinates.
Many of signs posted along the trail will give you additional geologic information about the area.
Please stay on the paths and do not attempt to cross the river to the Arch.
A natural bridge is formed by erosion of rock through various forces which includes water (both frozen and running) and wind. Bridges are more easily formed in soluble rocks such as sandstone, limestone, and basalt. Greenville Falls and Arch stand as a testament to the forces of nature and time. At Greenville Falls State Nature Preserve, Greenville Creek drops approximately 20 feet over ledges of resistant dolomite at the head of a 25 foot deep gorge cut into the Silurian Lockport dolomite. Just downstream from the falls, on the north wall of the gorge, is the natural arch. The spring near the top of the cliff has eroded back into the cliff along a layer of softer rock. This surface water, flowing down a vertical joint that intersects the roof of this small rock shelter, has separated the outer part from the cliff face thus making the arch.
Even though this medium arch remains mostly hidden from sight on the north wall of the gorge, it can be seen from the bottom of the riverbank steps. At the right time of the year, visitors to the park can also see state endangered species of plants that include: Harebell, Wand-lily and Limestone Savor. Great Blue Heron and Kingfishers glide along the watery gorge while rock bass, green sunfish, rainbow darters and small mouth bass swim in the waters of Greenville Creek. Visitors can enjoy all this while visiting this out-of-the-way park.
To log this cache please email us the answers to the following questions. Include a picture of the arch with your answers.
1. What is the material of the arch?
2. What is the span of the arch - the actual length of unsupported rock?
3. What is the evidence of change in the arch?
YOU MUST EMAIL US THE ANSWERS TO RECEIVE CREDIT FOR THE EARTHCACHE
From Ohio Geological Survey:
Underneath a widespread cover of young glacial sediment laid down in the last million years, Ohio is underlain by sedimentary rocks older than 250 million years: mostly limestone and shale, laid down in gentle, shallow seas. The oldest rocks are of Ordovician age, in the southwest; overlying them in a sweep over to the southeast border are (in order) Silurian, Devonian, Mississippian, Pennsylvanian and Permian rocks.
Deep beneath these is the ancient core of the North American continent, sloping away to the Illinois Basin to the southwest, the Michigan basin to the northwest, and the Appalachian Basin to the east. The part that isn't sloping, in the western half of the state, is the Ohio Platform, buried some 2 kilometers deep.
Ohio produces a great deal of coal and petroleum as well as other mineral products such as gypsum and aggregate.
For more information see the Geology of Ohio category
www.ohiodnr.com/geosurvey
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