A day of collecting Cretaceous fossils on the southwestern coast of France

La Barde, France — Today Team France returned to the Gironde Estuary on the southwest coast of France to study the Upper Cretaceous (Campanian) fossiliferous limestones and marls. We visited new sites and some we scouted out last week. Above is Pointe de Suzac, just south of Royan, where the Aubeterre Formation is well exposed. It was another beautiful day. Rather cool, in fact, during the morning.

The oyster beds we’re interested in are very well exposed here. The shells appear to be in random orientations, likely the result of storm waves stacking them up in piles.

In fact, at the outcrop is the modern equivalent: recent oyster valves piled together.

The southern side of Pointe de Suzac shows at least six of these oyster beds in the Aubeterre Formation, each separated by a thin marl rich in erect bryozoan fragments. The bedding planes are also exposed here, giving us a three-dimensional view of the deposits.

The sediments below the oyster beds are rich in other fossils. Macy found regular echinoids, rudists, pectenids, unknown flat bivalves, and isolated large oysters. The unit is thoroughly riddled with Thalassinoides shrimp burrows.

The branching fossils here are bryozoans. The small disks are large foraminiferans.

The headlands of Pointe de Suzac are dominated by thick concrete bunkers and gun emplacements that were part of the “Atlantic Wall” built by the Germans in World War II. Note the battle damage on this one.

This area held the last pockets of German resistance to the Allies in Europe. It was heavily bombed and shelled in 1945 during the liberation of Royan, which was a horrible event for the local French citizenry.

Later in the day we returned to the roadcut above Plage des Nonnes to see the oyster beds in the Aubeterre Formation. Macy and Paul are examining the shells in, again, six beds, separated by the same fossiliferous marls.

Not all localities are beautiful in France! Our last stop of the day was in a parking lot in Mirambeau. Here we looked at a very bryozoan-rich part of the Barbezieux Formation.

Another successful day. Thank you again to Paul for the expert guidance and driving!

Location GPS Unit Position
Pointe de Suzac 168 Aubeterre N45° 34.933′ W0° 59.352′
Pointe de Suzac south 169 Aubeterre N45° 34.599′ W0° 59.382′
Mirambeau 170 Barbezieux N45° 22.211′ W0° 34.252′

About Mark Wilson

Mark Wilson is a Professor of Geology at The College of Wooster. He specializes in invertebrate paleontology, carbonate sedimentology, and stratigraphy. He also is an expert on pseudoscience, especially creationism.
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