TOPOGRAPHY. The predominating natural fea ture of Spain is the great Iberian tableland which occupies the middle and much of the northern portion of the peninsula—a very compact, lofty, and mainly treeless plateau sloping as a whole to the west. The surface of the tableland rises from 1000 to 3000 feet above the sea, and in its highest part, on the edge of the Iberian Moun tains, which wall in Castile on the east, it is 3500 to 5000 feet high. This lofty plateau is crossed by many mountain ridges called sierras, the most important of which are the Cas tilian Mountains in the centre of the king dom (Sierra de Guadarrama and Sierra de Gredos), which divide the extensive high plains of 01(1 Castile from those of New Castile. The northern limits of the tableland are the Canta brian Mountains, the western continuation of the Pyrenees. and the southern limits are the Sierra Morena, which is nothing more than the steep edge of the plateau separating Castile from An dalusia. The highest mountains of the tableland are those of the central region, such as the Plaza Almanzo• (8730 feet) in the Sierra de Credos, and the Pico de Pecialara (7890 feet ) in the Sierra de Guadarrama: but these summits rise scarce ly 5000 feet above the general level of the pla teau. Sonic of the depressions between the moun tain ranges are narrow valleys drained by many rapid rivers, and communication across the sier ras from valley to valley is difficult.
The long unbroken chain of the Pyrenees forms a mighty barrier on the side of France. They form a wall of exclusion over which no highways have been built, the mountains being circumvented only by roads at their extreme ends. The highest peak of the Pyrenees (which is situated on the Spanish side of the boundary) is the Pico de Aneto (Pic d'Anethon), whose summit is about 11.160 feet above the sea. The
Sierra Nevada, in the extreme south, close to the coast, attains an elevation of 11,420 feet, in Mulahacon, the highest mountain in Europe (re garding the Caucasus as not belonging to Europe) outside of the Alps.
The alternation of mountain and river valley in Spain is very conspicuous—first the Canta brian Mountains and the Duero River in the north; then in succession the Olinda rra ma Moun tains and the Tagus, the Toledo Mountains and the Guadiana, the Sierra Morena and the Guadal quivir, with the Nevada Mountains, in the south. The coast throughout nearly its whole extent is bordered by mountains, giving it a very rugged character, and there are few openings that may be converted into good harbors. The coasts are further impaired for shipping by dangerous cur rents which tend to throw vessels on the shore. Barcelona has the only really first-class harbor. Spain contains two great low plains. One is the plain of Aragon in the northeast, through which flows the Ebro, which drains the greater part of Northeastern Spain. This plain extends between the Pyrenees and the Iberian Mofintains, and is walled in from the Mediterranean by the Catalonian Mountains. The other is the Anda lusian plain in the southwest, traversed by the Guadalquivir River and extending between the Sierra Morena and the Sierra Nevada. These plains, like the narrow and comparatively short coastal plains, are among the most fertile regions of Europe, but are of small extent compared with the wide-spreading tableland.