The natural site of the fountain of Tonne corresponds to a line of resurgent springs that we follow on the slope of the right bank of the Charente valley; they correspond to the outcrop of the base of a bench of clayey limestone from the Upper Jurassic. In the same geological situation, we find the fountain of La Faye, that of Font des rentes, the source of Ladoux in Marsac, the Font Pélerine not far from Bouchauds, as well as further south, the Breuillerie and the Pierre Levée on the commune of Trois-Palis. As in any karstic-type hydrogeology, the water from the fountain arrives in the open air after a long underground journey; even in periods of summer low water or severe drought, the source remains supplied. A narrow: pipe cut in the rock allows to concentrate the waters at the place of their exit. The very high concentration of carbonates in the water causes the precipitation of these in the form of solidification of porous rock which advances into the upper basin of the fountain. The fountain is also a favorable environment for a micro fauna of amphibians, frogs and salamanders, and the embankments that surround it see the appearance of pentecostal orchis purpurea (orchids) every year. The village of Tonne was only connected to running water from 1966, so the fountain was used until that time. It was restored in 1992 by the inhabitants of Vindelle, then in 2001 through an integration project which restored the pavement that surrounds it. The path is listed on a pilgrimage route to Santiago de Compostela.