The mediterraneen area offers a large variety of karsts which are sometimes similar, such as the vauclusian springs, but also with functioning and evolution differences which are often linked to the litho structural context and to neotectonic. The karst described in this study doesn’t have a scientific literature like some of its famous neighbors. And yet it has natural and outstanding archives in galleries at different karstification levels. These archives allow to reconstitute part of the long history of the entrenchment of a mediterraneen fluviatile valley. The large underground networks and the cave levels in the Coronat massif are the main characteristics of the Villefranche karst. The alluvial sheet conservation in the Têt valley in the gorges of Villefranche varies according to altitudinal levels. The most recent alluvial terraces can be continuous, the middle ones can be discontinuous and the highest ones have disappeared. On the other land the underground environment protects allogeneous sediments, coming from the Têt, at all levels. This is really important for the study of this karst. In lower levels of karstification, we can study the spatio temporal relation between the valley and the endokarst. This can be done thanks to the fluviatile archives which can be found where the valley is nearly as high as the large underground networks. Which allows to connect the morphogenesis of these networks with the lowes and middle alluvial terraces of the Têt on the section of the Villefranche gorges. On the other end in the higher levels of the karst there is no alluvial sheet on the slope. The study of the erosion forms and the fillings of the cavities will allow us to know the incision rhythm of the Têt valley. The datings cosmogéniques realized on sediments endokarstiques of two levels of conduits of the massif of Coronat show a karstification from the lower Pliocene and allow to propose a speed of section of Tet about 0,54cm / century.