Near Yellow Springs in Greene County, Ohio — The American Midwest (Great Lakes)
— Part of the Clifton Gorge/ Glen Helen Complex —
Ohio’s bedrock is all sedimentary. It was laid down upon the floors of the ancient oceans which periodically inundated the state. Conditions changed over the eons in these waters, dictating the different types of sediments that we now see as bedrock. Compaction over subsequent millions of years, compressed the materials into rock.
Ohio’s general bedrock types include sandstone, shale and limestone. The first two are formed from sediments washing into the sea from nearby land masses. Sandstones and comglomerates represent periods when coarse-grained and larger materials were introduced from relatively swift flowing rivers. Shales are former from finer sediments such as muds.
As seas receded and the resultant lowlands grew lush with swamp vegetation, the coal measures of eastern Ohio were formed. As seas alternately flooded and withdrew from the region, salt waters killed the vegetation, and brought in the sand and mud seen today as layers of coal interspersed with sandstone and shale.
Ohio’s sedimentary rocks form layers with the oldest strata at the bottom. These layers dip slightly to the southeast and northwest in the corners of the state while they are fairly level from Cincinnati north to Toledo. This dome or arch is a feature of the bedrock itself while surface erosion has cut evenly across the state. Therefore, different layers are exposed across Ohio with the oldest at the center of the arch and younger layers in the southeast and northwest.
Clifton Gorge of the Little Miami River here at John Bryan stands in sharp contrast to the relatively flat landscape of most of western Ohio. Rock and soil debris, spread over three fourths of the state during the Pleistocene Ice Age, buried most old bedrock valleys. Here, however, the story is obviously different.
The continental ice sheet blocked the preglacial routes of many streams
During the period 420 million years ago when this bedrock was formed, all but the southern extremeties of the state were covered by water which teemed with life. The shells and lime precipitants that accumulated hardened into limestone and then changed into the magnesium rich dolomite seem in the park today.
A spring walk through the gorge is a very pleasant experience. A wild diversity of wildflowers flourish in the rich soils while warblers sing from the budding trees. Nowhere is the show of bluebells and hepatica quite so pretty as beneath these towering cliffs and on the banks of the pristine, officially designated Wild and Scenic River.
Erected by Ohio Department of Natural Resources.
Topics. This historical marker is listed in this topic list: Environment.
Location. 39° 47.653′ N, 83° 50.468′ W. Marker is near Yellow Springs, Ohio, in Greene County. Marker is on Orton Memorial Parking Lot, on the right when traveling north. enter John Bryan State Park through the main gate at St Rt 370. Continue on park service roads to the east as far as possible, approx. 1 1/2 miles, Touch for map. Marker is at or near this postal address: 3790 State Route 370, Yellow Springs OH 45387, United States of America. Touch for directions.
Other nearby markers. At least 8 other markers are within walking distance of this marker. Paper Mill (approx. 0.2 miles away); Orton Memorial (approx. ¼ mile away); Camp Birch (approx. 0.4 miles away); Nature's Calendar (approx. half a mile away); Clifton Gorge State Nature Preserve (approx. half a mile away); Clifton Gorge (approx. 0.6 miles away); Clifton Gorge Marker (approx. 0.7 miles away); Historical Clifton (approx. 0.8 miles away). Touch for a list and map of all markers in Yellow Springs.
More about this marker. Text is VERY extensive, other than the Lion’s Club Marker in West Liberty, this is the wordiest marker I have found yet.
Credits. This page was last revised on June 16, 2016. It was originally submitted on September 15, 2014, by Rev. Ronald Irick of West Liberty, Ohio. This page has been viewed 794 times since then and 15 times this year. Photos: 1, 2, 3, 4, 5, 6, 7. submitted on September 15, 2014, by Rev. Ronald Irick of West Liberty, Ohio. • Al Wolf was the editor who published this page.