From a geological point of view, the Queyras is made of two kinds of rocks to the east, shales lustrous Piedmont, occupying About two-thirds the size of the valley, and west, limestone and limestone chips, among which extends cervical Izoard (common Arvieux) Col Tronchet (common Ceillac) close strip of gypsum and cargneules. The Queyras in , General William inserts on page 21, a card very clear and easy to understand the geology of Queyras.
This opposition is geologically very important historically and culturally. In the schist belt gloss, there are six common Ristolas, shelter, Needles, Moline, Saint-Veran Chateau-Ville-Vieille, and a part of the common Arvieux, which form the Queyras history - one that merges with the old escarton which corresponds to the Township of needles. In contrast, in the Queyras limestone are Ceillac and the eastern part of the town of Guillestre, which did not participate in the history of Queyras.
Moreover, this dual structure determines two types of geological landscapes, very different from each other. To the east, between Guillestre and the Guardian Angel is the Gorges du Guil, then the Combe du Queyras, dug into the limestone Queyras, made of rock barriers, sheer cliffs, deep gorges. General William, p 20, writes: "When the traveler goes back gorges Guil Guillestre between (...) and the confluence of the River Arvieux, it is difficult to defend against a feeling of oppression, even anxiety, among the gigantic cliffs that dominate both sides and seem ready to crush their mass. In this
Queyras limestone, there are two distinct geographical realities. The first, known as the Gorges du Guil, Guillestre extends to the House of the King, the second, known as the Combe du Guil, will the House of the King in the Guardian Angel.
Further east, landscapes change. The steep cliffs are succeeded by wide valleys, gentle slopes, vast pastures. The geographer Raoul Blanchard, leading expert and author of the Alps a short monograph of Saint-Veran, and explains why: "The shales are soft (...) and they were left largely cut by erosion until to give these broad saddles that contrast with the narrow lanes which are carved the hard rock of Briançon. About Molines valleys and Saint-Veran (between 1900 and 2100 meters), he said: "(...) has retained a real hanging valley, with soft shapes, very different from those of the Guil, Queyras and unique to both his favorite model and its vast dimensions. "
