The Finosa locality, 4 km east of Ghisoni (central Corsica), is situated in the northern part of a series of pyroclastic and detrital formations of probable Permian or upper Carboniferous age. The section studied includes ignimbrites with long sinuous xenoliths of recrystallized rhyolitic glass, alternating green and red tuffs, agglomerates, arkoses, breccia, and limestone. The mineralization is stratiform, emplaced by substitution in the rhyolitic tuff at the expense of the vitreous matrix. Mineralization in the green tuffs was arrested by the lateral passage to the red facies. The main locality is situated where the tuffs are crushed by a protuberance from the roof of the underlying granite basement complex. The Finosa mineralization exhibits marked vertical zonation. The minerals encountered are listed according to their relative abundance showing a predominance of sphalerite and galena. These mineralized deposits are classified as mesothermal beds impregnated and substituted in the collapse zones of the siliceous rocks. The mineralization is related to the terminal phases of the Hercynian orogeny.