A lava flow that no longer is one

About 4 million years ago, the Cantal volcano, whose highest point today is the Plomb du Cantal, was still sending lava southwards. One of these flows came to a stop on the Lacroix-Barrez plateau. As it cooled, the basalt shrank and split into columns, like the basalt organ pipes you can see elsewhere in the Cantal.

Much later, during the great cold spells of the Quaternary, frost shattered those columns. The pieces slid and piled up further down. So what you see today is not a frozen lava flow but a scree field: a mass of basalt blocks rounded by time. The name has stuck, though, and nobody here calls it anything else.

The same basalt turns up in the houses of the Carladez: the Monaco tower in Mur-de-Barrez is built of it. The volcanoes also shaped the landscape around Valon, down to the course of the Truyère, as we explain in our guide to the Truyère gorges.

The "Du magma à la pierre" walk

The people of Lacroix-Barrez made the lava flow the centrepiece of their Sentier de l'Imaginaire, one of six in the Carladez (see our guide to the Sentiers de l'Imaginaire). The trail tells the story of the Earth, from magma to the arrival of the monkeys, and is waymarked with a red monkey. At the edge of the lava flow, a stone giant waits for walkers: this is the place for a break and a snack.

  • Start: Place du Cardinal-Verdier, in front of the church in Lacroix-Barrez, where you can park.
  • Loop: 3.4 km, about 1 hr 30, 51 metres of climbing, between 732 and 777 metres above sea level. Graded very easy.
  • Access: free, all year round.
  • From Valon: 6 minutes by car (5.5 km).

From the same starting point, the La Fage route (2.6 km, 1 hour), waymarked by Binocle the mole, goes round a pond. The two loops can be joined into an easy 6 km mountain-bike circuit, number 8 of the Carladez routes.

Our tip

Come in spring or after rain, when the moss on the blocks is bright green. Wear good shoes if the children want to climb on the stones, as some of them wobble underfoot. The Sentiers de l'Imaginaire trail guide is given out free at the Carladez tourist information office in Mur-de-Barrez (+33 5 65 66 10 16).