Spain

The Meseta is divided into northern and southern submesetas, representing respectively the ancient kingdoms of Castile and Aragon, by a central cordillera. This central cordillera consists of a series of crust-block mountains formed by successive frac tures and vertical movements and extending en echelon north eastward from the Atlantic coast near Lisbon to the Nudo de Albarracin where it connects with the Iberian ranges. It divides the basin of the Douro river from that of the Tagus. There are lofty peaks reaching above the line of perpetual snow in the sierras of this central cordillera. The highest peak, the Plaza del Almanzo (8,727 ft.) in the Sierra de Gredos, is only a little lower than the highest of the Cantabrian peaks, while the Pico de Pefialara in the Sierra de Guadarrama reaches 7,888 ft. Even these highest crests are, however, only about 5,000 ft. above the general level of the Meseta. Between the Sierra de Guadarrama and the Sierra de Gredos and between the latter and the Sierra de Gata are high irregular surfaces filled with hills and parameras. Parallel to the western part of the central cordillera between the basins of the Tagus and Guadiana rivers are the Montes de Toledo, a shorter series of sierras that form a denuded highland of relatively low elevation and are separated from the Iberian ranges by the section of the Meseta known as La Mancha. Their highest point is Las Villuercas (4,920 ft.) in the Sierra de Guadalupe. Their westward extension into Portugal is known as the Montafias de Alentejo. The Sierra Morena is an even less continuous range than the central cordillera or the Montes de Toledo. Its westerly extension into Portugal ends at the rocky headland of Cape St. Vincent.

Geologically, geographically, and politically the Meseta is the true Spain. On all sides it is in general remarkably isolated from the coast so that the passes on its border and the river valleys that lead from it to the coast and to the Ebro and Guadalquivir depressions have been from earliest times geographical features of the highest importance. On the north-west, communication between Le6n and Galicia is furnished by the Sil river which at an early date was followed by military roads and now forms part of the route of the railway to the port of Corunna. In the Can tabrian mountains the passes are fairly numerous and over them lie the routes of several railways connecting the interior with the ports of the Bay of Biscay. The two most remarkable passes in these mountains are the Pass of Pajares which carries the rail way from Leon to Oviedo and the port of GijOn and that of Reinosa which leads down to the deep valley of the Besaya and is crossed by the railway from Valladolid to Santander. The east part of the range is crossed by railways from Burgos to Bilboa and San Sebastian, the latter following the picturesque gorge of Pancorbo and crossing the range at Idiazobal.

On the north-east the valley of the JalOn river affords the most important communication between Madrid and the Ebro depression. At an early date an important military road followed

this depression. It is now traversed by the railway from Madrid to Saragossa. Farther south the southerly extension of the Iberian ranges long made direct communication between Madrid and Valencia difficult, and even now, although a branch line connects the Jalon valley with the coastal railway a short dis tance north of Valencia, the main communications between Madrid and the east and south-east coasts are across the south eastern part of the Meseta and the hill country between the Meseta and the Mediterranean.

The descent from the Meseta to the depression of the Guadal quivir is comparatively gradual but passes through the eastern part of the Sierra Morena are few, the principal one being the Puerto de Despefiaperros where the Magafia river, a tributary of the Guadalimar, has cut a deep gorge that the railway from Andalusia to Madrid follows in its ascent to the Meseta.

The central cordillera also offers considerable obstruction to easy communication between the northern and southern sub mesetas, although the hilly intervals between the sierras afford comparatively easy routes. Carriage roads cross the three main passes in the Sierra de Guadarrama (the passes of Somosierra, in the north-east, Novacerrada near the Pico de Pefialara, and Guadarrama a few miles south and west), while the railway from Madrid to Segovia passes through a tunnel close to the Guadar rama Pass and that from Madrid to Avila crosses the south western portion of the same sierra by a remarkable series of tunnels and cuts. The Sierra de Gredo has a road across it con necting Avila with Talavera de la Reina by way of the Puerto de Pico; but for the most part there are only bridle-paths across this sierra and the Sierra de Gata and no railway crosses either of them.

The Ebro and Baetic Depressions.

The Meseta is bordered on the north-east and on the south by two great transverse de pressions. The most striking is that on the south, known as the Baetic depression now deeply eroded by the bed of the Guadalquivir. It is a gigantic fracture that has cut like a knife across all the strata of the Meseta and stands out with remark able clearness from Cape St. Vincent to the eastern end of the Sierra Morena. The present Baetic depression is believed to be the remains of a strait which, up to the Tertiary period, con nected the Mediterranean with the Atlantic. Later, on account of movements that produced the Penibaetic cordillera by which the present depression is bounded on the south and south-east, this strait was reduced to a gulf opening only to the Atlantic, and in time converted, whether by further uplift or by sedi mentation alone, to the present valley. The sedimentary deposits of the Guadalquivir which flows along the most abrupt border of the depression at the foot of the Meseta has been built up on the materials worn off from the Meseta during the period of submergence and the sediments of marine origin to form the present fertile valley of Andalusia.