GMS Field Trip

GMS Field Trip
Eocene Fossils in Georgia
Saturday, February 7, 2015

Collecting Eocene fossils in this quarry is always a lot of fun. Because of quarry requirements, the trip is limited to 25 participants and the list filled up quickly. Fortunately, a few people on the waiting list were able to make it in.

Mike Reagin and Henry Frantz explained the layers we were seeing. The top layer is what was once called the “Flint River” layer. It has a lot of red clay and limestone pebbles. The next major layer down is the Twiggs Clay. It is a gray layer and contains Fuller’s Earth, a very fine, absorbent clay. The next layer is where we were digging – the Clinchfield layer. We also noted a very thin green layer. Some pieces we found in the quarry indicate the layer contains glauconite, an iron mineral that forms in an environment where there is decaying matter that causes reducing or low oxygen conditions, hence the green color.

Sand dollars were probably the most abundant fossil where we were digging. Many specimens popped out right away. Al Klatt found the name of the sand dollars in a Cobb County Gem and Mineral Society newsletter: Periarchus pileussinensis. Most of the sand dollars we found had the bottoms visible and the top in matrix, but I saw several that were the other way around.

In addition to sand dollars, people were finding some other interesting fossils. Al found what at first appeared to be a bone, but on later inspection he said it was not a bone, though it may still be a fossil, possibly coral, or it could be a trace fossil, maybe a burrow cast. He did eventually find a bone, but the animal has not been identified yet. There were several nice gastropod shells as well as scallops too. Henry Frantz was on a mission to find sharks’ teeth. He found a few broken bits and some ray teeth, but Al was more fortunate. He found a complete tooth!

My usual technique for collecting the sand was not in the offing (no well-washed gullies this time) so I took home a few baggies of material that must be screened. Joe Summerour gave me some great advice before the trip to collect loosely consolidated limestone, then soak it and screen it. Once the weather cooperates with some warmer afternoons, I’ll be able to screen the material and look for micro-fossils.

Thanks to the quarry people and the field trip participants who helped with identification and digging, it was a great trip!

Lori Carter
On behalf of Charles Carter, GMS Field Trip Chair
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