The Paleozoic Era

Image credit Ray Troll

The Paleozoic Era encompasses the beginnings of life as we know it today. It begins with the Cambrian Epoch approx. 542 mya up to the worst extinction in the history of the Earth - the end Permian Extinction, often referred to as “the great dying”, around 252 mya. During the Cambrian we get to see the first evidence of the development of mobility in life, and we see a large uptake for armor - a hint that life in the Cambrian, though primitive, was not devoid of predators. Combining these evolutionary revelations the Cambrian spawned one of the most prolific and dominant animals in the history of the planet - the trilobite. Here in South Carolina, the only known Paleozoic fossils are from the Cambrian period. The only known exposure was discovered in 1982 near the town of Batesburg-Leesville quite by accident - as most important paleontological discoveries seem to happen.

Finding the Trilobite in the Haystack

Samson, 1984

On March 2nd, 1982 the University of South Carolina was conducting a field exercise mapping the Batesburg Quadrangle (“Quadrangles” are the USGS term for subdivisions of the US into manageably sized areas, typically 7.5 minutes latitude by 7.5 minutes longitude). During this mapping exercise one of the students, Sara Samson, leaned down to tie a loose shoelace. When doing so, she noticed what looked like a fossil of some sort on a loose rock by her foot (pictured). At the end of the day Art Snoke and Don Secor, who led of the exercise, were shown the item. They had to be convinced they weren’t being conned for a case of beer (there was an offer of a case of beer for the first person to find a fossil during this class, as it was well known no fossils had ever been found in the survey area before), but after sufficient convincing they were overjoyed. There had been one partial trilobite recovered in a creek near North Augusta, SC prior to this discovery, but there had been no success in determining the origin of the fossil, nor success in reproducing the find. This made the discoveryall the more exciting, as upon returning to the locality it was found to be highly fossiliferous and dozens of fossil trilobites were recovered. However, upon further investigation, it was noticed the recovered trilobites weren’t American in origin. This begs the question - Where did the Carolina Slate Belt come from?

The Carolina Slate Belt

Samson, 1984

The Carolina Slate Belt has long been thought to be an exotic terrane - that is it was not originally part of South Carolina. Interestingly, the fauna recovered from the Batesburg-Leesville site helps solidify this to be the case. The slate belt itself consists of metavolcanic and metasedimentary rocks and runs from Georgia to Virginia, and doesn’t compare favorably to the inner piedmont series. Trilobites found include ones with large eyes and with affinties to Gondwana, pointing to deposition in a shallow sea displaced from Laurentia (North America). The best theory is that it was part of a volcanic island chain off the coast of Africa or South America (Gondwana at the time) and eventually became attached to Laurentia at an unknown time. The slate belt is comprised of three formations: the Richtex, Persimmon Fork and Asbill Pond formations. The Asbill Pond formation is dated to the middle Cambrian, approximately 500-510 mya. The other formations range from precambrain to mid-Cambrian.

The reason fossils are found in the condition they are in the slate belt is due to the original sedimentary deposits being metamorphosed. This has caused strain on the fossils, and we are lucky to still have any at all. In the Batesburg-Leesville locality a different of 500 feet takes you from mudstone with very defined and easy to break bedding planes to a layer where bedding planes have been eradicated by the immense heat during the deposition of the volcanic rock nearby. Fossils vary drastically over a small area from impressions, to stains, to fair 3D preservation.

Note on Collecting

The land owners of the Batesburg-Leesville locality have requested at this time not to have collectors visit their property for the purposes of fossil collecting. I am respecting their wishes and would be remiss not to mention this at the end of this page and strongly encourage that interested parties do the same. The family has been through a lot, and the fossils are not going anywhere. As always - please respect property owners and the legalities of collecting wherever you are for the preservation of the hobby, and the benefit of science. Thank you.