342 M. F. Le Play on the Geology of [May 



trict, as might hence be expected, are very imperfect. M. 

 Le Play states that by far the most accurate is that of Bory 

 de Saint Vincent. The author has, however, constructed a 

 geological map, which, as far as his observations extended, 

 may be considered as correct, and as a most valuable con- 

 tribution to Science. 



The central portion of Estramadura, about Talarrubias, 

 consists of a plain, which is elevated about 550 metres 

 (1804 feet) above the level of the sea. The town of Puebla 

 d'Alcocer, lies 50 metres above this plain, or 602 metres 

 (1975 feet) above the sea, which is almost exactly the alti- 

 tude of Madrid, and of the plain of New Castile, which 

 insensibly sinks towards the south-west, as it approaches 

 Estramadura. M. Le Play considers this plain as bear- 

 ing a striking resemblance to that of the Western Hartz, 

 not only in its corresponding elevation, but likewise in its 

 geological structure, vegetation and climate. 



It preserves an agreeable surface, being distinguished by 

 ancient, inclined, and occasionally crystalline rocks, and 

 traversed by a few rivers, whose channels are about 160 or 

 170 feet deep, and of whose existence the traveller is not 

 aware till he approaches the ravine in which they run. 

 Even the largest of these, the Guadalquiver, is fordable in 

 June, above Seville, and the Guadiana is seldom in a state 

 to prevent its being crossed in the same manner. 



The valley of the Guadiana is depressed 190 feet below 

 the level of the transition plain. The alluvia of its banks 

 rarely extend above 200 feet from either bank, and fre- 

 quently one of its banks consists of a vertical wall of schist 

 or greywacke. As the river leaves the Sierra d'Alcocer, 

 however, its escarpments disappear, and plains extend on 

 both sides. The valley of the Tagus is also deep, and where 

 it enters Estramadura, this river appears to force its way 

 with difficulty through a mountainous district. Very dif- 

 ferent, however, is the character of the Guadalquiver, 

 which traverses the plain of Andalusia, whose elevation 

 little exceeds the level of the sea. The plain, which extends 

 on the left between Cardova and Seville, is not raised more 

 than fifty feet above the bed of the river. 



The ridge of the Sierra Morena follows the direction of 

 the Guadalquiver, from Cordova to Seville, which is a west 



