is aligned more or less parallel with the regional foliation. Across strike it is only 2.5 kilometers wide. Its intrusive granitic nature is demonstrated by occasional hornfelses along its edges. Like the very similar Saut-du-Saumon orthogneiss the Corgnac granite also intruded during the middle Ordovician about 470 million years ago. The granite was overprinted at about 350 million years ago during the regional metamorphism under retrograde conditions. Its chemical composition defines it as a subalkaline monzogranite. Two very different facies can be distinguished in the Corgnac granite: cataclastic granitic facies in the south. porphyroclastic orthogneissic facies in the north. The equigranular, sometimes porphyric, grey to rose-coloured granitic facies contains the following minerals: interstitial quartz plagioclase – often zoned, of basic composition microcline – often perthitic biotite Accessory minerals are muscovite, zircon, apatite and opaques. All these minerals were altered during the greenschist facies retromorphism. Biotite and quartz for instance were broken cataclastically, plagioclase was invaded by muscovite and clinozoisite and rutile needles exsolved from biotite. The granitic facies has produced several smaller, porphyric, microgranitic apophyses. The orthogneissic facies is derived from the granitic facies, it only underwent a stronger ductile deformation. The facies presents itself now as a banded augengneiss with amygdular eyes of microcline and plagioclase surrounded by foliation minerals like very fine quartz, albite, granular clinozoisite and mica lamellae. The biotite is often chloritized. The shear sense has not been determined, but most likely is right-lateral judging by the Corgnac granite being part of the southern section of the Thiviers-Payzac Unit. Estivaux Granite The synkinematic Estivaux granite is a calc-alkaline massif of magmatic origin that was deformed heterogeneously about 346 million years ago during the Tournaisian. Like the Saut-du-Saumon orthogneiss its shape is also squid-like developing tentacular arms at its northern gneissic and also mylonitic end. The granite is about 8 kilometers long in the NW-SE direction and 3 kilometers wide across strike. In the northeast the left-lateral Estivaux strike-slip fault separates the massif from rocks of the Upper Gneiss Unit. In the southwest it is surrounded by the Thiviers sandstone. Its southeastern limited is outlined by the Clan river. The granite develops four different facies: melanocratic facies. leucocratic facies. white facies. pink facies. Its mineralogy (in the melanocratic facies) shows the following composition: As porphyroclasts: orthoclase – can attain a grain size of 4 millimeters, the porphyroclasts are partially broken and filled in by microaplite. Essential minerals