Edisto Beach Fossils

Along the way, we heard that Edisto Beach (SC) was a well known area for finding fossils... 

Archaeologists have known about the paleontological fossil site at the north end of Edisto Island at Jeremy Inlet since at least the 1960s. The Charleston Museum has fossils from this place dating back to at least the 1820s and possibly earlier.  The inlet is just over a mile walk along the beach, North from the Edisto Beach State Park.

Looking South at low tide from Jeremy Inslet

Approximately 47,000 years ago, the Laurentide glacier began expanding over what’s now Canada.  Much of the water that existed in the atmosphere became trapped in this growing sheet of ice.  As a result of decreasing precipitation, the Atlantic Ocean receded many miles to the east of what today is the coast of South Carolina and other ocean-bordering states.  Somewhere to the east of what would become Edisto Beach 40,000 years later, grass, shrubs, and finally trees colonized the new top soil that had formed from sea bird guano, plant detritus, pulverized shells, sand, and river deposited mud.  This soil built up on top of a fossiliferous geological formation dating to the early Miocene when the area was deep under the ocean.  

The later Pliocene and early Pleistocene strata washed away, creating what geologists refer to as an unconformity where the late Pleistocene strata overlay the Miocene – strata from the ages in between are missing here.  Conditions were favorable for fossilization here, and many Pleistocene age vertebrate fossils became preserved over thousands of years.

Now, the glacier has melted and the Atlantic Ocean has once again advanced.  Strong currents blast through both the Pleistocene strata, and the Miocene formation, eroding slabs of fossils into the sea where the waves carry them to the shore.  Edisto Island is a productive fossil site, albeit the fossils are from three different ages and are totally mixed, so that Miocene and Holocene marine fossils are found right next to Pleistocene land vertebrate specimens.  Shark’s teeth, including those of the giant great white shark, Carcharodon megalodon, as well as an impressive the list of Pleistocene mammals.

Outflow from Jeremy Inlet at Edisto Beach

The fossil deposit has yielded a rich assortment of Pliocene and Pleistocene fossils. These include both land and marine creatures both big and small. The land animals include mammoth, mastadon, giant sloth, bison, horse, camel, capybara, deer, elk, large cats, various turtles, and numerous small mammals. The marine animals include whales, dolphins, manatees, many species of sharks and rays, drum fish, and numerous other species.

Jeremy Inlet at low tide