Hautza

Baïgorry Valley

The eastern valley features straight-sided hills separated by valleys with friable sandstone subsoils and outcrops, rapidly eroded by rain and frost, observable at the Aldudes sand quarry and Bihurrietabuztan ravines. In contrast, the western valley saw red sandstones deposited in the early Mesozoic (circa 225 million years ago) after the folding of the primary bedrock. This thick layer rims the Aldudes Massif, dipping toward Baztan and rising near the Nive Valley, forming a steep escarpment from Bidarray to the Col d’Ispéguy, peaking at Hautza (1,306 m or 4,285 ft) just 400 meters (1,312 ft) from the Spanish border. These red sandstones, also found along the Larla (700 m or 2,297 ft) and Yarra (812 m or 2,664 ft) ridges interrupted by the Nive gorge below Eyheralde, are quarried under the misnomer "La Rhune slabs."