1835.] Estramadura and the North of Andalusia. 357 



form with the meridian an angle of 15° towards the west, 

 and will run from Cape Ortegal to the pillars of Hercules. 

 It thus points out a series of dislocations, which all assume 

 the same direction, and which formed the isthmus which 

 united Spain with Africa. The revolutions during the 

 secondary period acted principally in the south of Spain. 

 At the end of the secondary period, the revolution which 

 produced the Pyrenees, gave to the mountains running 

 from Cape Ortegal to Catalonia, the elevation which they 

 at present possess. The coast between Catalonia and Cape 

 Creuss was formed by the elevation of the Pyrenees, and 

 several islands varied the surface of the sea, which ex- 

 tended from the Alpuj arras chain to Corsica. On its 

 shores lived the echini and terebratulce of Cordova. But a 

 great revolution speedily supervened, which formed the 

 coasts of Catalonia, Valencia and Murcia, and elevated the 

 western Alps. 



Cape Forcas in Africa and the islands of Alboran are in 

 the same line of elevation, and probably, constituted 

 another isthmus, which joined Africa with Spain. The 

 observations of Silvertrop upon the tertiary strata of 

 Murcia, demonstrate that the third tertiary formation, 

 reposes in horizontal layers on the inclined strata of the 

 second era, confirming the theory of Beaumont. The 

 strait of Gibraltar was formed by the same rupture which 

 produced the western Alps. At this period, an immense 

 pressure appears to have been created under the peninisula, 

 which elevated it to its present position, and projected 

 crystalline rocks or ophites through its substance. Hence 

 it is, that we find these rocks in mountains of different 

 ages, and that the latter affect an east north-east direction, 

 which characterizes the elevation at this period. The great 

 snowy chain which separates the two Castiles, the Sierra 

 Morena, presents the character of mountains formed suc- 

 cessively, and then re-united at a more recent period by 

 another eruption. The latter are composed of three dis- 

 tinct parts, in relation to the stratification of the rocks and 

 its direction. This revolution formed the Spanish Alps, the 

 Sierra Nevada, and the coast between Malaga and Gibral- 

 tar. By raising the Southern coast of Spain the lands which 

 united the latter with Africa were lowered, and the Strait of 



