This small Nature Preserve holds the most complex story of geology found in all of the Trek Birmingham sites. To truly understand what happened, come visit, walk the trails, and touch the fossils imbedded in the canyon walls.
The first glimpse into the twisted geologic history of Turkey Creek is the deep Blue Hole at Bull Frog Bend. This favorite swimming and fly-fishing spot provides a look at ancient rock layers set on end by the slow, intense folding of the Ridge and Valley limestone and sandstone. This rock was once an ancient horizontal stream bed where Turkey Creek cut through the Miocene uplift.
Serious folding of the layers turned the creek bed on its side. There’s more evidence high up on the hill on the other side of Turkey Creek Road from Blue Hole. A short but steep scramble straight up this hill takes you to the base of another vertical rock. Evidence of an overthrust fault can be seen in the layers like a blanket folded back on itself. The movement of the massive rock layers moved older rocks on top of younger. Folding on a massive scale happened where the older hard coal-laden rock of the Warrior Coal Field Shale Hills held firm as the younger layers of Conasauga Limestone were thrust over and then cracked in a diagonal line across Jefferson County.
Read more about thrust faulting in our summary of the Geology of Oak Mountain State Park.