Spain

The Ebro depression forms a deep ravine between the north east corner of the Meseta and the Pyrenees. Its two bordering walls converge to form an angle at the point where the depression is shut off from the Mediterranean by the Catalan coast range through which the Ebro river has now cut a tortuous gorge. At one time the depression was occupied by the sea which pene trated by way of the Gulf of Rosas but did not extend through to the Bay of Biscay. Later when the Catalan coast range emerged the depression was converted into a closed lake. The definition of the Ebro river and the successive terraces which now characterize both sides of the depression were brought about by the later uplift to which is due the present architecture of the Pyrenees.

The Ebro valley is divided into two sections by spurs from the Pyrenees on the one side and from the Sierra del Moncayo of the Iberian ranges on the other. The uppermost of these, a plateau of between f ,000 and 1,300 ft. above sea-level, is only about one-fourth the size of the lower portion. The valley of the Guadalquivir is also divided into an upper and a lower sec tion as indicated by the change in the course of the river from a due west to a more south-west direction. The small upper valley is of considerable elevation while the much larger lower valley is mainly lowland and from Seville to the sea is composed of a perfectly level and marshy alluvium (Las Marismas).

Mountains Outside the Meseta Border.

The Pyrenees (q.v.) form a continuous wall between Spain and France with an average altitude higher than that of the Alps. Their snow capped crests reach their highest point in the Pico de Aneto (10,965 ft.) in the great central massif of granitic rocks that form the core of the range. Few trails and no railroads cross the Pyrenees. The Catalan coast range which separates the Ebro depression from the coast is the youngest range of the peninsula and all evidence indicates that the region has suffered movements that have taken place in the Quaternary period. It represents the upper portions of a land mass now in large part submerged beneath the Mediterranean. The peaks Monseny (5,713 ft.) and Montserrat (4,064 ft.) are the outstanding crests. Erosion has moulded them into beautifully picturesque forms. Nearer the coast a series of hills of low elevation border the Catalan range throughout its whole length.

The Baetic system of the south-east part of the peninsula has been described as due to a series of thrusts that had their focus farther south and forced up against the rigid mass of the Meseta the land mass located in front of it. It is generally accepted that

a long longitudinal fault which extends from the lower course of the Segura river to the Genil river divides the system into two groups. The mountains to the south of this fracture are known as the Penibaetic system. They lie near the Mediterranean coast and are considered to be prolonged across the Strait of Gibraltar by the mountains of the Riff. The great block of the Sierra Nevada of the Penibaetic system contains the highest crests of the peninsula and reaches its greatest altitude in Cerro Mulhacen (11,417 ft.). It is completely Alpine in character with glacial cirques, lakes, and moraines. The Penibaetic system includes at its eastern end the volcanic zone that forms the Cape de Gata. The extension westward from the Sierra Nevada to Point Mar roqui appears to be cut by a series of transverse faults. The mountains north of the Penibaetic fault, though not exhibiting the high crests of the Penibaetic system, have a much broader area of high altitudes. They close the eastern end of the Baetic depression and extend eastward to form the Cape de la Nao. The dividing line between them and the Iberian ranges is gen erally placed at the Jiicar river.

Rivers and Lakes.

The main water divide of the peninsula follows rather closely, in the north, east, and south, the border of tlae Meseta and the greater part of the drainage is westward by four large rivers, the Tagus (Spanish Tajo, Portuguese Tejo), Douro (Spanish Duero), Guadiana, and Guadalquivir. Only a limited part of the north-east corner of the Meseta is drained by the Ebro on account of the barrier of the Iberian ranges, and all the remaining rivers which drain to the Mediterranean are short as compared with those draining to the Atlantic. All the large rivers of the Atlantic slope rise in Spanish territory. The Tagus and the Douro have their lower reaches in Portugal and the lower Guadiana is partly in Portugal and partly on the boundary. Only the Guadalquivir and the Ebro, of the larger rivers, are entirely in Spanish territory. The longest of the rivers is the Tagus (565 m.). The rest in the order of their length are the Guadiana (510 m.), the Douro (485 m.), the Ebro (466 ITO, and the Guadalquivir. The Minho, which divides the Cantabrian from the Galician mountains, and its tributary, the Sil, which rises in the north-west corner of the Meseta, is much shorter.