Forty-three species, the majority of which are figured, have been recorded in the late Eifelian and the Givetian of the Pic de Vissou quarry. Six new species are introduced: Samarella porrecta nov, sp., Cytherellina musculosa nov. sp,, Healdianella? dorsostriata nov. so., Ampuloides mourezensis nov, sp., Ampuioides vissouensis nov. sp. and Bairdiocypris postsoetenica nov. so. The ostracod assemblage belongs to the Eifelian ecotype and is indicative of a well oxygenated and moderately deep water environment below the level oi wave action, and generally below storm wave base. Sedimentological analysis allows recognition of six major microfacies families ranging from open marine environments, below or close to the storm wave action, to relatively shallow environments near the fair weather wave base. The deepest environments are dominated by hemipelagic communities rich in Styliolina while the shallow ones show echinoid and bryozoan communities reworked from a destabilized shelf. Sequential analysis does not allow direct bathymetric comparisons. It shows however that the transitional Eifelian-Givetian layers recorded a clearly transgressive event following a three-step evolution.