Pocket Caves
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Erosional Cave
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The fossil beds at the Falls of the Ohio provide living proof (or once living proof) of the ocean and coral reef that existed here more than 350 million years ago!
The coral reef, as we find it today, stretches from Louisville north to Indianapolis. Nowhere else in the world does such a large, exposed fossil reef of this period exist. The 220-acre fossilized reef lies exposed only at the Falls of the Ohio!
Technically speaking, the Devonian Period ocurred between 395 and 345 million years ago. During that time, Indiana and Kentucky languished beneath a warm, tropical sea, and were located about twenty degrees south of the equator. During the Devonian age, fish were the most advanced life forms in the aquatic world. Because jawed fish first appeared then, paleontologists dub the Devonian period the "Age of Fish." A shifting of the earth's continents eventually moved this part of the earth's surface to its current location.
During the 45 million year span of the Devonian Period, the oceans deposited layer upon layer of lime silt, sediments, and plant and animal remains. Of these deposits, five distinct fossil layers lie exposed at the Falls:
- The uppermost layer - or the youngest rock - is the Paraspirifer Acuminatus Zone.
- Second is the Fenestrate Bryozoan-Brachiopod Zone.
- A six-inch-thick layer called the Brevispirifer Gregarius Zone follows.
- The Amphipora Ramosa Zone, commonly called the Cave Zone. Pocket caves have developed here due to the powerful erosive powers of the Ohio River rushing across the rock. This zone occurs along the vertical cliffs of the river channel, where the cutting force of the river reaches its peak.
- The oldest and most remarkable layer is the largest to be exposed. It bears the name Coral Zone because of its abundance of fossil corals - so many, in fact, that visitors find it difficult to walk on this layer without stepping on fossils exposed in the bedrock.
- To assist in fossil identification, the interpretive center provides an educational website HERE.
Erosion is the process by which the surface of the Earth gets worn down. Erosion can be caused by natural elements such as wind and glacial ice. But anyone who has ever seen a picture of the Grand Canyon knows that nothing beats the slow steady movement of water when it comes to changing the Earth.
The key to erosion is something called "fluid flow." Water, air, and even ice are fluids because they tend to flow from one place to another due to the force of gravity. Of the three, liquid water is the most common agent of erosion because there's so much of it on the surface of the Earth.
The Falls of The Ohio River is one of the neatest places that I have visited. There are lots to explore, so give yourself plenty of time. It's a challenging hike in when the upper gates are closed (Usually August - October), or by boat when the river level is below 12-feet on the lower gage. and well worth the visit if you are fascinated by fossils, rocks and erosional features of the earth.
At the listed coordinate you will see the effecte of this erosion. Dozens of caves and grottos have been carved into the limestone over thousands of years along this stretch of the exposed fossil bed. In fact, if you tap your hiking staff on the surface of the limestone along the way, you'll notice a hollow sound, evidence that erosional caves exist right under your feet! Feel free to explore but BE CAREFUL!
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The area is generally available August - October due to dry weather and low water.
IF YOU HIKE - BEFORE YOU GO:
Call this number: (502) 775-5056 and listen to the one-minute recording.
The recording will give you important information on the river level above and below McAlpine dam. You will also hear how much water is running through the upper and lower spillways of the dam (one-mile apart).
If there is ANY water running through the upper spillway, this HIKE IS NOT POSSIBLE - YOU CANNOT CROSS.
When the upper gauge is at pool, the level will be 12.0 feet. The lower level (below the dam) MUST be 12.0 feet or LESS also.
If the lower gauge is above 20 feet, the reef will be submerged.
To LOG THIS CACHE
You must be at the coordinates to log this find. There are a plethora of reasons why you can't make it here. If you couldn't quite make it for whatever reason, sorry, it's NOT A FIND.
Post a picture if you wish, I hope you take a few!
And to demonstrate the educational benefit of this EC, determine the answers to these four questions:
1. How old are these fossil beds?
2. What is the elevation at the coordinate?
3. How tall are the cave openings?
4. What is this rock called?.
Note: The Ohio River is part of the state of KENTUCKY. Please consider this when 'going for a state'.
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Please email your answers and post your photo first, then LOG THE FIND. Do not wait on a reply from me. FINDs which do not meet logging requirements will be quietly removed.