The coal-field of Palencia, a continuation of that of Oviedo, is in course of development by the Northern Railway Company. Smaller coal-fields of great local importance exist in the provinces of Cordova, Seville, Gerona, Burgos, Cuenca, Guadalajara, and Ciudad Real; that of Gerona, although of small extent and very friable quality, has already occasioned the construction of a railway of considerable length. Iron is mainly obtained from Biscay, Oviedo, Murcia, and Almeria, but is abundant in other provinces. Lead is worked chiefly in Murcia, Jaen, Almeria, Badajoz, and Ciudad Real; the presence of antimony or of a predominating admixture of blende is very common, but Spain is on the whole the most important lead-producing country in Europe. Copper is obtained mainly from the Rio Tinto mines and others in Huelva; also from Seville, Palencia, Almeria, and Santander; but many other districts contain veins yielding more or less of copper ore. Zinc has been chiefly procured from superficial pockets of calamine in Santander and the neighbouring districts; but in the form of blende it is widely distributed in association with lead. Silver ores are worked in Almeria and Guadalajara. The immense impregnation of cinnabar of Almaden, in Ciudad Real, affords nearly all the mercury, but a little is obtained from other mines in the same province and in Oviedo, Granada, and Almeria. Manganese is obtained from Huelva, Oviedo, Teruel, Almeria, Murcia, and Zamora. Nickel ore is worked in Malaga; cobalt in Oviedo and Castellon. Tin occurs in a number of small veins in Galicia; and in the rocks of Salamanca, Murcia, and Almeria, as well as in diluvial gravels. The Spanish side of the Pyrenees contains numerous veins of argentiferous lead, many of copper, and some of cobalt, nickel, argentiferous copper, pyrolusite, &c., few of which are worked. The lead-mines on the border between Catalonia and Aragon supplied the Carlists with ammunition during the late civil war. The fact that more than 12,000 concessions of mines already exist in Spain, while a large number of lapsed concessions may be found, affords a better idea of the mineral wealth of the country than the enumeration of the mines actually worked.