Archive for June 7th, 2017

Revisiting the Gironde Estuary for our last day of fieldwork in southwestern France

June 7th, 2017

La Barde, France — Today Paul Taylor, Macy Conrad (’18) and I had our last fieldwork in France for this expedition. We returned to sites along the eastern shore of the Gironde Estuary to study the Biron Formation (Campanian, Upper Cretaceous), thus completing our three-part stratigraphic survey along with the Barbezieux and Aubeterre Formations. Macy is seen above crouching at the Caillaud South locality.

This is a view of the Caillaud South cliff from the south. The camera can’t convey how very white the rocks are and still keep the rest of the image in a correct exposure. A salt marsh is in the foreground.

The Pycnodonte vesicularis oysters are common at the Caillaud south locality, but they are well cemented into the limestone matrix. We’re looking here at an articulated shell with the right valve on top. This would have been the oyster’s living position.

There is a normal fault exposed in the Caillaud. It is still Biron Formation in either block, but the facies are slightly different on one side from the other.

This part of the estuary was the site of a significant Gallo-Roman settlement.

We also revisited the north side of Caillaud, where again it is Biron Formation with about a meter of Barbezieux on top of the cliff. The structures to the left are fishing towers.

Bryozoans are abundant in this exposure. Here is a nice bryozoan colony, probably the cyclostome Meliceritites, according to Paul.

Talmont-sur-Gironde from the south. This tiny place receives half a million visitors a year. Note the tidal mudflat in the foreground. We were near low tide.

This is an aerial view of the village, courtesy of Wikipedia. It is nearly surrounded by the sea at high tide. The village was founded in 1284 by Edward I of England. In 1652 it was destroyed by the Spanish. I’m surprised it survived World War II.

I’ll end this post with a French wildflower of some type we saw today. It symbolizes the beautiful countryside we had the privilege to explore. Thank you again to Paul and Patricia Taylor for hosting us so elegantly. Paul was also a spectacular field driver on the small country roads, and his knowledge of the fossils and stratigraphy is astonishing.

We have one more day in southwestern France, and then Macy and I head back to Paris.