Révision d'un site paléontologique célèbre : Saint-Prest (Chartres, France)

Abstract

The site of Saint-Prest is located in a karstic depression opened in the upper part of a slope of the Eure Valley. This depression is first filled by periglacial alluvial sands and gravels of the river Eure (very high terrace), then covered by a clayey sand where the interglacial fauna has been found. Above there are two formations: periglacial sands and cailloutis deriving from the plateau-deposits and a sandy loess. This complex older than 800 Kyr, restricted to the depression, is covered by saalian and weichselian loesses. Many papers have been written about the fossiliferous site of Saint-Prest since its discovery one and and half century ago: its age is not far from the upper boundary of the Villafranchian period, and some scholars thought to recognize in it numerous trails of activity from an early man ancestor. A new analysis of the fauna shows that 11 mammalian species are actually present: the Deperet's Mammoth Mammuthus meridionalis depereti COPPENS and BEDEN; the evoluted form of the Etruscan Rhino Dicerorhinus etruscus brachycephalus (SCHROEDER), GUÉRIN; the Stenon's Horse Equus stenonis COCCHI; the Carnute Elk Alces carnutorum (LAUGEL); the Verticornis Deer Praemegaceros verticornis (DAWKINS); a large relative to the Red Deer, Cervus sp. 1 cf. elaphus LINNÉ; a small relative to a specifically undetermined Fallow Deer, Cervidae sp. 2 aff. Dama sp.; the Forest Bison Bison schoetensacki FREUDENBERG; the large European Hippo Hippopotamus major CUVIER; the Boisvillette's giant Beaver Trogontherium cuvieri boisvilletti (LAUGEL); the Short-faced Hyeana Pachycrocuta brevirostris (AYMARD). The mammoth is the most common species (174 remains), followed by the Rhino (21 remains) and the forest Bison, other Mammals being always less than 10 remains each. Saint-Prest is the type-locality for three of these taxa, the mammoth, the Elk and the Giant Beaver. Such a fauna allows us to date the site from the MNQ 20 standardzone, with an absolute age of roughly 1 My. The mammalian community of Saint-Prest clearly indicates an open forest landscape under a temperate wet climate, near a river (Eure).