CHAPTER III.

GEOLOGY AND MINES.

Even in geological features Spain is a land apart. Divided from the rest of Europe by the regular Palaeozoic band of the Pyrenees, the rocks of the Peninsula are only susceptible of separate study. Hence no consistent geological history can be deduced from the fragmentary and superficial observations that as yet form the basis of the geological map of Spain. A few striking features and geological statistics may however be presented; and the recently-published map of Botella, as well as the mass of valuable matter already collected by the _Comision del Mapa geologico de Espana_, are an earnest that Spanish geology will soon occupy a place corresponding to its peculiar interest.

A mass of Granitic, Cambrian, and Silurian rocks forms the central plateau of Spain, extending in a south-easterly direction from Galicia to the valley of the Guadalquiver, and spreading to the north-east, as shown by the chains of the Guadarrama and the mountains of Toledo, to terminate in the Celtiberian range, running nearly parallel to the Ebro by Soria and the Moncayo. In this mass the main folds of the strata appear to run in a south-easterly, the main fractures in a north-easterly, direction; whence the gridiron arrangement of the mountain chains and river valleys, directed by these leading features of the rocky structure. Great buttresses of the Carboniferous formation occupy the corners of the central mass, to the north and south-west, and occasional patches of its upper and coal-bearing beds are scattered over the interior. The whole valley of the Ebro occupies a trough of Secondary rocks, which extend in a south-easterly direction from the Bay of Biscay to the Mediterranean, forming a wide boundary to the older central mass, and running along the north coast towards Oviedo. The Secondary formations of the Ebro sweep over the chain of the Moncayo on to the central plateau by Burgos, Soria, and Calatayud; and their latest member--the Upper Cretaceous--advances in two long tongues on to the granite of the Guadarrama, and far to the east of Madrid, it being probable that at least this member formerly extended over the central plateau. Another wide band of Secondary rocks, running in a north-easterly direction, forms the long strip of Andalusia south of the Guadalquiver; and by Valencia and Cuenca this band is widely prolonged to the Ebro basin; otherwise, a narrow and interrupted strip along the south coast, and a bay-like expanse from the Atlantic, between Lisbon and Oporto, are the only Secondary tracts of the Peninsula. These Secondary rocks are however in great part concealed by Eocene Tertiary beds, formed in marine gulfs in the valley of the Ebro and the Guadalquiver, and overlaid by Eocene and Miocene fresh-water deposits; the latter being also represented by vast lacustrine sheets, which contemporaneously accumulated, and conceal the crystalline and palaeozoic formations in the elevated river basins of the central primary plateau. Patches of Pliocene sands and clays along the Mediterranean coast, sheets of diluvial gravels below the mountains, and alluvial sands along the larger rivers represent the local and most recent effects of water and ice.

The consequences of this general structure are apparent on every hand. The population of Galicia is in many respects similar to that of the Portuguese mountaineers, who occupy the same band of naked granitic and primary rocks. The inhabitants of the varied and fertile Secondary band of Andalusia and Valencia have many traits in common. The Biscayans are a race apart, like the labyrinth of Cretaceous precipices and green rainy valleys which they inhabit. All are distinct from the Castilians, whose monotonous and isolated existence on the vast treeless steppes of crumbling Tertiary sands and marls that carpet the primary plateau 2000 feet above the sea has deeply influenced their character. Finally, the inhabitants of the Ebro basin, a region where the dry Tertiary soil of Castile is combined with many characteristics of the Secondary tracts, afford a curious mixture of Castilian with Basque or Valencian traits. The inhabitants of the greater Spanish cities are of course products of civilization, not of the soil.

Of the visible surface of Spain 37 per cent. is occupied by Crystalline and Palaeozoic rocks, 34 per cent. by Tertiary, 19 per cent. by Secondary, and 10 per cent. by Quaternary deposits. The Palaeozoic rocks are greatly contorted and fractured, the Secondary scarcely less so, the older Tertiary are crumpled up against the flanks of the mountain chains, and even upturned Pliocene deposits testify in some places to the late continuance of the movements that have contributed to the production of the peculiar elevated character of the Peninsula. The remains of undoubted volcanoes are confined to the insignificant groups of Olot, Cabo de Gata, and Ciudad Real, but innumerable dykes and bosses of igneous rock are scattered over the primitive plateau where unconcealed by Tertiary sheets, and are also frequent in the Secondary tracts. This abundance of igneous injections is intimately connected with the exceptionally metalliferous character of Spain, while the fractured and contorted condition of even the latest rocky formations has contributed to a general diffusion of mineral wealth.

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.

The quantity of mineral contained in the rocks of Spain is no less remarkable than the exceptional variety of its distribution; but owing to a series of adverse circumstances, the industrial production affords a most inadequate idea of the capabilities of the mines, if developed by a fair amount of capital and skill. The following figures, showing the production in 1875, are derived from the last official reports issued by the Spanish Government, and are certainly below the truth:--

Tons of ore Tons of metal exported. produced in Spain.

Iron 336,000 37,000 Lead 10,000 119,000 Copper 362,000 6,620 Zinc 43,000 3,820 Manganese 14,000 Mercury 1,425

These figures do not include the bar iron produced directly from ore in Spain, nor 160 tons of argentiferous copper ore, 89 tons of cobalt ore, and 440 tons of nickel ore. The silver extracted in Spain amounted to more than 16,000 lbs. troy, while four times that amount was contained in exported argentiferous lead. The coal extracted amounted to 666,000 tons, lignite above 27,000, sulphur above 3000, and phosphorite above 12,000 tons. The year 1875 was, however, peculiarly unfavourable to Spanish mining, and the working of the Bilbao mines, which now produce nearly 2,000,000 tons yearly of excellent iron ore, was then practically suspended by the Carlist war. All disadvantages cannot, however, arrest the steady increase of mineral production in Spain, although under more normal political circumstances the above figures would have been greatly exceeded.

The chief coal district is that of Oviedo, Palencia, Leon, and Santander. The coal-field of Oviedo, occupying an extent of 230 square miles, and including a large number of workable beds, is of excellent quality, but as yet little developed, owing to high railway tariffs, bad condition of ports, traditional prejudices, want of skill and capital, and of a local market for inferior qualities. These obstacles will probably soon be overcome, and the development of the associated iron ores afford an important field of enterprise.

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.

That such enormous mineral resources should have as yet yielded no greater results is easily explained. The Roman and Moorish workings, although traditionally of fabulous yield, are of small depth, owing to insufficient machinery for pumping. Till the present century, the working of mines was forbidden by the Spanish Government, with the object of favouring the development of the American colonies. The mining laws of 1825 and 1849, suddenly placing the acquirement of mines within the reach of every substantial peasant, produced a fever of speculation, and a recklessness in the application of unskilled labour, which naturally conduced to the discouragement of mining enterprise, while the recurring civil wars excluded foreign capital and skill. Spaniards have a mania for erecting smelting-works on the mines, a practice occasionally justified by difficulties of transport, but which has caused much loss of capital through inherent difficulties and want of metallurgical skill. Endless litigation, arising from the defects of the first mining laws, and the inexperience of the surveying engineers, contributed to ruin the small capitalists who had attempted to work the mines. Foreign capital is now the chief requirement. The existing mining law, greatly improved since 1868, is the simplest in Europe; the expense of a concession is almost nominal, and the royalties on ore are extremely moderate. Large mining adventures in Spain rapidly develope industrial conditions and profoundly affect the habits of the population. Even in times of civil war a _modus vivendi_ between the conflicting parties can be more easily secured than might be expected. The development of means of transport, already considerable before the last Carlist war, is being seriously resumed under the present Government. The Spanish peasantry, when suitably treated, will be found a fair-dealing, intelligent, and industrious class. It must, however, be remembered that in the peculiar physical, political, municipal, and fiscal conditions of Spain, no mining enterprise can safely be undertaken without thorough investigation of all the external circumstances, claims, and prospects concerned; since more mining speculations have failed from inattention to such matters than from any disappointment as regards the quality or quantity of ore.

P. W. S. M.