(a) Photo of the Oligocene strata near the Saint-Barthélémy farm showing the global pattern of the Oligocene which is twice overturned below younger Oligocene, forming two successive hook halokinetic sequences. (b) Zoom on one hook halokinetic sequence showing Oligocene overturned strata below younger Oligocene strata and the unconformity between. (c) Zoom on the unconformity. (d) Picture of casts of the crest of current ripples marks at the bottom of a bed, testifying that the Oligocene is overturned.