CANTABRIAN MOUNTAINS, a mountain chain which extends 30o m. across northern Spain, from the Pyrenees to the borders of Galicia, and near the coast of the Bay of Biscay. East of the pass of Leitariegos they are nearly parallel to the coast but to the west they trend southward between Leon and Galicia. Their western boundary is marked by the valley of the river Mino, by the lower Sil and by the Cabrera. Some geographers regard the mountains of Galicia beyond the Mino as a part of the same system; others confine the name to the eastern half of the high lands between Galicia and the Pyrenees, and call the western half the Asturian mountains. There are many local names for the subsidiary ranges within the chain. Intricate ramifications char acterize the chain, but almost everywhere, especially in the east, it is possible to distinguish two principal ranges, from which the lesser ridges radiate. One series of ranges closely follows the coast; and short swift streams flow down it into the Bay of Bis cay; the other series is loftier and there is a gradual descent to the high plateaux of Leon and Castile. Several large rivers, notably the Ebro, rise here and flow to the south or west. The breadth of the chain increases from about 6o m. in the east to about 115 m. in the west. Many peaks are above 6,000 ft. high, the highest, Pena Vieja (8,743 ft.), Prieta (8,304 ft.) and Espinguete (7,988 ft.), and an unnamed summit in the Penas de Europa (8,045 ft.), all being in the central ridges, whilst farther west are the peaks of Manipodre (6,837 ft.), Ubina (7,552 ft.), Rubia (6,331 ft.) and Cuina (6,575 ft.). A conspicuous feature of the whole region is the number of its isolated plateaux (parameras). From the pass of Leitariegos the Sierra de Jistredo and Montanas de Leon curve towards the east and south-west whilst the Sierra de Picos, Sierra del Caurel and other ranges curve towards the west and south east, and the two arms enclose El Vierzo, an old lake-basin now an alluvial plain drained by the upper Sil. The Cantabrians are rich in coal and iron; an account of their geological structure is given under Spain. They are crossed at many points by good roads and in their eastern and central parts by several railways.