Selective History: A Geologic Wonder
Stone Bridge 1955 (before '56 rock fall ).
Ed Beckler gets geology lesson from Dr. Brian Turner, 1970's
Geology of Natural Stone Bridge and Caves, a more recent review.
Surveys by the National Speleological Society conclude that the Stone Bridge appears to be the largest natural marble cave entrance in the East. In November 1956, nearby road work may have led to the fall of a 900 ton piece of rock from the stone bridge. No one was around to see it, but David Heldt was the first to witness the result.
In the early 1970's, Natural Stone Bridge and Caves owner and president Ed Beckler consulted with experts to learn the geology that created the caves is rare to this part of the continent. Separate but parallel hydrologic systems have resulted in the existence of two types of rock. Marble limestone rock and older volcanic material known as pink granite gneiss exist side by side.
During the latest ice age, an unusual East/West fault exposed this ancient rock to ferocious waters from retreating glaciers. Recent mapping and surveying by the National Speleological Society determined that the resulting Stone Bridge appears to be the largest natural marble cave entrance in the East. It measures up to 180' wide and 62' high.
Violent waters return to the caves in the form of floods each spring. So the cave systems constantly evolve along with varying water levels.
The Natural Stone Bridge 2004