Puy de la Poix, la source de bitume de la Limagne

Clermont-Ferrand

Near the Clermont-Aulnat airport, a small mound about three metres high lets bitumen seep out. In a cavity about a metre wide, the hydrocarbon mixes with very salty water and forms a rivulet of nearly thirty metres. It rises along faults from rocks of the Oligocene of the Limagne. According to a specialised website, the Gallo-Romans knew the spring and used it for its sticky and waterproofing power; Charles IX is said to have visited it in the 16th century. Finds, including a menhir, show human presence from the Bronze Age. During the Second World War the German army pulled down the menhir and set up an anti-aircraft defence turret. In the 19th century at least one company attempted a serious borehole: according to the British engineer Redwood (1896), a well was dug to 50 m, then abandoned for lack of money. The flow, then estimated at one litre a day, was too low for industry. The staff maps of 1820–1866 still show the puy; it has disappeared from current maps. From 2009 to 2012 the Conservatoire des espaces naturels d'Auvergne and the City of Clermont-Ferrand cleared and developed the site, with a plaque in enamelled lava.

Getting there: Free: nature reserve accessible to all, north-east of the puy de Crouël, near the Clermont-Aulnat airport, by the chemin de Praslong (sign ‘le sentier du bitume’). The puy no longer appears on modern IGN and BRGM maps. Coordinates from OpenStreetMap (summit), which agree with a tourism page to within about 20 m.

Opening times and access details are given as a guide only: check before you set out.

Ambient sound