Ceiling, upper part of the cave.


Place where several rivers meet.


The gour is a concretion, like a natural dam across an underground flow.


In caving, a siphon is an hydraulic phenomenom that consists in a completly flood gallery. It is a particularly dangerous place to cross for cavers as it does not let the diver know how long it takes to cross.


In caves, mineral masses formed by calcium carbonate precipitation, most of the time calcite or exceptionally aragonite. According to the type of flowing or physico-chemicals conditions, different kind of concretions are formed. The colours depend on the differents organic acids met by the infiltrating water.

Straw stalactite

Thin concretion consisting in a little pipe in which infiltrating water flows. Each drop of water leaves a little calcite ring at its extremity, and so the pipe grows up. Also called macaroni because of its resemblance with the famous pasta.


Thin concretion formed by streaming water on a vertical or inclined wall.


Conical concretion developing from a cave ceiling. A stalactite is mostly formed by a succession of straw stalactites of which central canal is blocked. With stalagmite, it is one of the most common forms in caves.


Concretion more or less massive, cylindrical or conical, growing from the floor of a cavity. The drop of water falls on the ground and puts down a little bit of calcite. By stacking calcite, stalagmite will come up.


Calcite is one of the crystalline form of calcium carbonate (CaCO3). This is one of the most common minerals on Earth, but the forms taken in caves are typical and must be protected.