The story begins nearly 500 million years ago, in a shallow sea
churning with new life. Small shell forming animals with a variety
of the other marine life began their life and death cycle.
Countless millions of years later their shells and remains, now
accumulated on the sea floor, had compresses on the hardened into
what is now known as limestone.
The earth, tormented within, began a period of restlessness.
Upheaval and movement resulted in the formation in the Appalachian
Mountains. Rock Layers, formed on the ancient sea floor, were
lifted up and folded. The intense pressures from this upheaval left
their mark, fracturing and shifting the rock, forming cracks and
fissures.
Rainwater, churning swirling, searching for the sea, seeped
through the cracks and fissures, dissolving the weaker areas and
carving underground channels. Sinkholes and a network of
interconnecting passages and tunnels tell this story today. The
ever moving water, dissolving various and sundry minerals on its
journey, including iron and magnesium, redeposited these passengers
in limestone layers below. Reinforced be new minerals some
limestone layers become harder and can be identified today by the
rusty patches on their sides.
The forerunner of today’s North River began cutting into
the layers of limestone, and the ancient sinkholes and the
limestone around them were exposed to view. As the erosive process
isolated the towers, the hard upper layers of Chert protected the
limestone beneath from the destruction, forming vertical pillars of
stone. At times during this erosive process the North River lapped
against the pillars, and chimneys, at levels as high as 80 feet
from the ground.
The Natural Chimneys as you see them today, then, are erosion
remnants of a former fissure cave system, a geologic curiosity
unique in the eastern United States. Although they have looked much
as you see them for as long as man has inhabited this area,
processes of erosion continue their relentless work. In some future
time, far distant for man but short in geologic terms, these mighty
stone pillars will have been worn completely away.
To log this Earthcache, please email me the answers to the
questions below.
1. What were the tunnels and caves remnants of?
2. What was the Intruder?
3. What is the field used for?
4. Post a photo of you and the towers in your online log.