The Gravenne volcano

The main stream is nearly 5 kilometers long; its colonnade is made of powerful prisms and its false colonnade presents locally a flow in balls (along the road D 26, with 150 meters of the crossroad with D 536).
Small flank flows are relatively numerous on the slopes and at the base of Gravenne (Soubeyrols SW). These are small emissions, from a few decimeters to a meter of power. This phase of activity seems late compared to the main edification of the cone. The fact remains that the abundance of screes does not make it possible to systematically estimate the exact spatio-temporal relations between the various formations. It is near "Black Rock" that are best observed small late and thin flows (a few meters). One of them, with entablature, is also visible near Pourcheyrolles.