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.