(Lexington County). Peachtree Rock is the namesake of a 305-acre South Carolina Nature Conservancy preserve located on the Sandhills of Lexington County, sixteen miles southwest of Columbia. The rock itself is a small, highly eroded remnant of sandstone that was perched on a small, tapered base, like an inverted pyramid. In late 2013, the rock fell off this base due to natural processes of erosion and rainfall, as well as occasional vandalism.
Peachtree Rock and the surrounding sandstones were formed in a marine environment during the Middle Eocene epoch. Walking from Peachtree Rock toward the dirt road at the entrance to the preserve, the observer traverses sediments of progressively younger ages: Upper Eocene marine sands, river-deposited sands from the Miocene epoch, and sand dunes from the Pliocene and Pleistocene epochs.
The geology of the Peachtree Rock preserve reflects the conditions that existed during the Eocene to the Pleistocene epochs. During the Eocene epoch the sea levels globally were much higher than they are in the twenty-first century, and the climate was warmer. Many species of marine animals swam in seas that covered what is now the coastal plains. The nature of the fossils found at Peachtree Rock give evidence that they were not formed in deep water, but rather in shallow water near shore. By the Pleistocene epoch the sea levels had fallen and the Peachtree Rock area was above water.
Other interesting features of Peachtree Rock preserve are found by a small waterfall that runs over sandstone preserved by a silicified caprock. The small Eocene marine fossils located near the falls consist of shell hash and shrimp burrows as trace fossils. The preserve also contains a wide diversity of plant life that can be observed by walking the trails that wind more than a mile through the ridges and dunes of the area.
Able, Gene. Exploring South Carolina: Wild and Natural Places. Rock Hill, S.C.: Palmetto Byways, 1995.
Murphy, Carolyn H. Carolina Rocks! The Geology of South Carolina. Orangeburg, S.C.: Sandlapper, 1995.