The Cham des Bondons and its limestone plateau extend to the southwest of Mont Lozère over about 3,86 sq miles (10 km²). It connects the granite base of Mont Lozère to the limestone plateau of the Causse de Sauveterre. Two stranges mounds of black marl, the Puech of Allègre and the Puech of Mariette, culminate at approximately 4,000 ft (1,220 m) and dominate the Tarn valley. The Puech of Allègre is rounded, while that of Mariette is tapered like a razor. The legend tells that the giant Gargantua, imagined by François Rabelais, would have brought back their limestone soil from the Causses in the sole of his clogs.