The granite and other igneous rocks form rounded bosses or prominent pinnacles, according as they are more or less subject to atmospheric decomposition; the pine and the Spanish chestnut flourish on their slopes; iron, lead, copper, tin, graphite, phosphorite, kaolin, steatite, and serpentine are among the products of these crystalline masses. The gneiss and crystalline schists that in part probably represent the Laurentian formation, contain silver, bismuth, molybdenum, and tin; while metamorphic rocks of unknown age are amongst the richest in mines, affording iron, lead, silver, copper, zinc, mercury, manganese, and graphite. The Cambrian formation, a mass of lustrous fissile slate, traversed by white quartz veins, furnishes lead, silver, phosphorite, and gold. The Silurian slates and quartzites yield iron, lead, silver, copper, mercury, manganese, antimony, cobalt, nickel, anthracite, and gold. A few limited patches of Devonian sandstones, quartzites, slates, marls, and limestones, afford iron, zinc, phosphorite, cobalt, and nickel. The Carboniferous series, occupying two per cent. of the surface, includes valuable coal-fields, the immense masses of iron and copper pyrites of the Rio Tinto, Tharsis, and other mines in the province of Huelva, besides iron, zinc, mercury, manganese, antimony, cobalt, nickel, and phosphorite in other districts. The silver-bearing metamorphic rocks of Cartagena, and a portion of the slopes of the Sierra Nevada are classed in the Permian formation. The Triassic conglomerates, sandstones, and variegated marls, which form the usual base of the Secondary rocks, are rich in salt, gypsum, and iron, and afford some copper and zinc. The Jurassic limestones and marls contain asphalte and bituminous slate. The Cretaceous--mainly Neocomian in the south, the Upper Cretaceous predominating in the north--contains the immense iron deposits of Bilbao; valuable beds of lignite resembling coal; lead, zinc, and asphalte mines in the northern provinces, and gold in Granada. In the Eocene formation, which includes the Nummulitic limestone that forms some of the highest summits of the Pyrenees, the celebrated salt-mine of Cardona, in Catalonia, is usually classed. The Miocene beds contain valuable sulphur deposits along the southern coast, and great accumulations of sulphate of soda on the arid steppes of Madrid and other provinces; while gypsum, in which Spain is probably richer than the whole remainder of Europe, is abundant in this formation. Lastly, some native silver is found in the Pliocene deposits of Almeria, and in the Tertiary clays of Guadalajara, while the later gravels of Galicia afford stream tin and gold, the last similarly occurring in Leon and Caceres.