WESTERN ALPS PALEOKARSTS FROM TRIASSIC TO EOCENE - In western Alps, before complete emersion during the Oligocene and Miocene, the marine sedimentation has been locally interrupted by three important continental phases: 1/ during Early Jurassic, in "briançonnais" domain; 2/during middle Cretaceous, in Provence area; 3/ during early Tertiary, in subalpine range and Jura. These locally and temporary regression are the consequence of tectonic activities in relation to the movements of eurasiatic and italo-african plates, which are at the edge of the alpine oceanic basin (Tethys). After an abstract on the tectonic and sedimentological history of western Alps, a description is given of continental formations (bauxites, fire-clay, clay with flints, siderolitic formations, white and ochrous sands, siliceous and ferruginous crusts) and karst phenomena elaborated during these regressions.