An artesian well is named for the French province of Artois, This region abounds in the wells which bring forth a supply of underground water. In a true artesian wells the water gushes forth like a natural spring; The crystal fountain is often warm and bubbly.
The water which supplies these wells is called artesian water. Actually, it is ground water trapped in a special rocky formation. The rain water seeps down to a layer of porous rocks and settles there. Above it is a dense layer of shale through which it cannot escape.
This formation puts pressure on the ground water. When a well is dug down to it, the pressure causes the water to bubble up in a spring or fountain. When the artesian water is very deep, it may be warmed by the interior of the earth.