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Pinnacle Rock, Kentucky's 300th EarthCache EarthCache

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Geocache Description:

Welcome to Kentucky's 300th EarthCache. Kentucky leads the Nation with the most EarthCaches!


Pinnacle Rock rises 1090' above Cumberland Gap, TN and another 200' above Middlesboro, KY. It is inside the Cumberland Gap National Park. You can drive most of the way up the mountain, but you will have to hike the last 1/4 mile.

History of the Pinnacle

For a hundred years or more, Pinnacle Rock has been a popular tourist spot. In years past, the road to the top was private and one had to pay a fee. Today, however, it is part of the Cumberland Gap National Park and it is free to drive to the top. Or, for the truly adventurous, you can hike to the top from the visitor’s center 1290 feet below. Once there, you will want to stroll the 1/4 mile, handicap accessible, walk to the Pinnacle Rock overlook where you will find spectacular views of the surrounding countryside, including the famous Cumberland Gap, the town of Cumberland Gap, TN, the city of Middlesboro, KY, and much, much more.

Pinnacle Rock is formed from the Pennslyvanian sandstone rock formation and sits high above the Cumberland Gap. Pinnacle rock is millions of years old and has been formed by wind, water erosion. This has been viewed by many visitors since the 1800s. Pinnacle Rock is still a very popular site for visitors at Cumberland Gap.

How was the Pinnacle formed?

It’s all about weathering. Weathering is the breaking down of rocks by various agents like water, wind, ice, earthquakes, plants, animals, humans. Some of the rock formations are more resistant to weathering and fractures in rocks can enhance weathering.

The Pinnacle was formed out of sandstone and limestone over millions of years of weathering. Running water is by far the main agent of erosion for Pinnacle Rock. Gravity is the force that causes water to run downhill and erode the sides of the Pinnacle. It is also causes erosion by causing rock falls and landslides.


Area geology

The outcrop of Pennsylvanian strata defines the limits of the Eastern and Western Kentucky Coal Fields. The Eastern Kentucky Coal Field is part of a larger physiographic region called the Cumberland Plateau which extends from Pennsylvania to Alabama. The eastern edge of the Eastern Kentucky Coal Field and Cumberland Plateau is called the Pottsville or Cumberland Escarpment. This escarpment is formed from resistant Pennsylvanian age sandstones and conglomerates. The escarpment is stepped in south central Kentucky because several thick, resistant sandstones are separated by less resistant shales. The manner in which the sandstones weather and are eroded along the escarpment results in sheer cliffs, steep-walled gorges, rock shelters, waterfalls, natural bridges and arches, and some of the most scenic areas in Kentucky.

Pine Mountain is another important physiographic feature of the region. Pine Mountain is best described as a 125 mile long ridge that extends from southwest of Jellico, Tennessee to Elkhorn City, Kentucky. It is 3,200 feet high in Letcher County. Pine Mountain is the direct result of a fault, called the Pine Mountain Thrust Fault. Near the end of the Paleozoic era about 230 million years ago, when the Appalachian Mountains were being built for the last time, a large block of the Earth's crust was pushed up and over the area that is now southeastern Kentucky. The pressures from mountain building caused the northeast edge of a block of Devonian, Mississippian, and Pennsylvanian strata to be pushed upward, forming a long mountain ridge. Because the fault pushed resistant Mississippian and Pennsylvanian-age sandstones upward, a resistant ridge formed, just like the Cumberland Escarpment.


The Geology of the Pinnacle

Across the Cumberland Gap, natural outcrops have exposed layers of rock strata. To a geologist, these layers are like the pages in a book, and each tells a part of the geologic story of Cumberland Gap. Almost all of the rocks exposed at the surface of the State are sedimentary rocks. Sedimentary rocks are layered, and can often be traced across broad distances at the surface and beneath the surface. Geologists can determine the relative age of sedimentary rock layers from the fossils they contain. Similar layers can be grouped into units of strata, just as pages are combined into chapters in a book.

Beneath the surface of the Pennsylvanian sandstone you will find Silurian and Devonian strata occur along with Mississippian, Ordovician through Devonian strata and so on. This is all exposed on the cliff side of the Pinnacle. Pennsylvanian rocks are only preserved in the Eastern and Western Kentucky, although all of Kentucky was probably covered by Pennsylvanian sediments at one time. Erosion has completely removed Pennsylvanian rocks from all areas but the eastern and western part of Kentucky. The Pennsylvanian Period, was a time of alternating land and sea. When the sea was out, the low coastal plains were covered with luxuriant forests of seed ferns, ferns, scale trees, calamite trees, and cordaite trees.

During times of heavy rainfall, thick accumulations of plant debris were deposited, which later became the coal that Kentucky is famous for. When sea level rose, which it periodically did, it covered the coastal peats and created large inland muddy seas. During these times, which lasted for many thousands of years, many types of marine invertebrates and vertebrates lived in Kentucky. Common Pennsylvanian marine fossils found in Kentucky include corals, brachiopods, trilobites, snails, clams, squid-like animals (cephalopods), crinoids, fish teeth, and microscopic animals like ostracodes and conodonts. You can find these types of fossils exposed in the layers of rock on the Pinnacle.

This is a National Park Service-approved EarthCache site. The information here has been reviewed and approved by the Cumberland Gap National Historic Park. Thanks to the staff for their assistance.


To get credit for this EC, post a photo of you on Pinnacle Rock with a state of your choice in the background just like in the picture above and please answer the following questions.

1. What are the different colors of sandstone on the Pinnacle formation?

2. What famous rock formations can you observe on the Pinnacle?

3. What large impact crater is viewable from the Pinnacle?

Cav Scout has earned GSA's highest level

Do not log this EC unless you have answered the questions and have a picture ready to post! Logs with no photo of the actual cacher logging the find or failure to answer questions or negative comments will result in a log deletion without notice. Exceptions will be considered if you contact me first (I realize sometimes we forget our cameras or the batteries die). You must post a photo at the time of logging your find. If your picture is not ready then wait until you have a photo.

Sources of information for the EarthCache quoted from the Cumberland National Historic Park. I have used sources available to me by using google search to get information for this earth cache. I am by no means a geologist.. I use books, internet, and ask questions about geology just like 99.9 percent of the geocachers who create these great Earth Caches. I enjoy Earth Caches and want people to get out and see what I see every time I go and explore this great place we live in.

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