The Mesozoic Era
Image credit Ray Troll
The Mesozoic Era is nicknamed the “age of reptiles”. During this time reptiles came to dominate the land, sea and sky and they would grow to incredible proportions. Sauropods the size of skyscrapers, ichthyosaurs rivaling the size of blue whales and pterosaurus with 40 foot wingspans this truly was a hostile and alien world. In South Carolina, unfortunately, there is not a great representation of the Cretaceous. Our exposures are quite limited - mainly found in the PeeDee river valley and in a few isolated places like Darlington and Myrtle Beach. On top of this, we only have the latest Cretaceous represented so we get a very narrow slice of the life that lived in SC during the Mesozoic. There are sedimentary rocks of Triassic origin in the Pageland area, but to date no fossils have ever been recovered from these. However, we still have had a lot of incredible finds even with the severe limitations imposed on the state. These include dinosaurs, mosasaurs, plesiosaurs, sharks, skates/rays, fish, turtles, crocs and invertebrates. Dinosaurs, being land-dwelling, are the rarest finds by a large margin having been swept out to sea to be fossilized. It is worth mentioning pterosaurs certainly lived in the state, however none have been reported.
Dinosaurs!
Hadrosaur tooth collected in SC
Dinosaurs - the animals that capture our imagination as children and give us our first insight into the prehistoric world. As mentioned previously, dinosaurs are quite rare in South Carolina. The best site in the state’s history is Stokes Quarry in Darlington, SC. Stokes Quarry is long closed now. We currently know of five distinct dinosaur groups in the state from these fossils: A large tyrannosaur (identified as Appalachiosaurus), ornithomimids, velociraptorines, maniraptorans, and hadrosaurs. Dinosaur remains include teeth, claws, unassorted bones and possible coprolites. All known dinosaur material originates from the Donoho Creek formation, or the Coachman formation (or time-equivalent strata). It should be theoretically possible for a dinosaur to be found in the PeeDee formation, however this is extremely improbable due to the deeper depositional environment of the PeeDee. For this to happen, a dinosaur would have had to die, fill with gasses during decomposition and float out into the sea, and then sink to the bottom and fossilize. This process is also known as “float and bloat” and does happen, but rarely. We can be quite confident there were more than five types of dinosaur alive in South Carolina during the Cretaceous. However, proving this remains left to either a dedicated or fortuitous (or both) collector that firstly recognizes what they’ve found and secondly reports it appropriately.
Cretaceous Exposures
South Carolina has three surface-exposed stratigraphic units, these being the Peedee, Donoho Creek, and Bladen Formations. These units range from the middle Campanian to late Maastrichtian, approximately 77-66 mya with a large gap missing from approximately 75-69 mya. This limits what we are able to find, as some of the mainstays of the Mesozoic like the ichthyosaurs were already extinct prior to the deposition of Cretaceous strata in the state. At Stokes Quarry it was determined that the unit producing Cretaceous-aged fossils was time-equivalent to the Coachman formation, approximately 78 mya. However, stratigraphic correlation with the Coachman formation was not able to be confirmed. It is inferred based on the faunal assemblage recovered from both Stokes Quarry and the Donoho Creek formation at Burches Ferry that they were at least highly influenced by a deltaic system, if not deposited within a deltaic system. This is evidenced by young reptilians such as mosasaurs, crocodilians and turtles as well as an abundance of sharks and rays with a shallow and warm-water affinities present. The Peedee formation, on the other hand, was a deeper water environment which is littered with exogyra and belemnites at Burches Ferry. At Burches Ferry at times of low water you can stand on the clay of the Donoho Creek formation and collect from a wall of PeeDee formation. At those same times of low water the Donoho formation can also be seen at Dewitt’s Bluff, and an extremely tough limestone that is extremely fossiliferous is visible at Allison’s landing. The most effective means of collecting here is breaking off chunks of limestone and dissolving it in acid, but this is a very slow and tedious process. The Bladen formation is intermittently exposed along the banks of the PeeDee river as well.
Note on Collecting
Please remember to respect all land owners and private property. Dewitt’s Bluff and Allison’s Ferry are wonderful public access localities that anyone can visit to learn more about the Cretaceous of South Carolina. These are where I would recommend any interested collectors visit. Other sites are private property and, as such, require land owner permissions to access. Make sure to do proper research and obtain permissions before entering any private property. A fossil collected without permission is useless to science, and the purpose of this site is to promote paleontological science in SC. Thank you.
References
Schwimmer, David R., et al. “A LATE CRETACEOUS DINOSAUR AND REPTILE ASSEMBLAGE FROM SOUTH CAROLINA, USA.” Transactions of the American Philosophical Society, vol. 105, no. 2, 2015, pp. i–157. JSTOR, http://www.jstor.org/stable/24398224.