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



axis of the granite basin of Torrenulano and Hinogosa, from 

 west 12° north to east 12° south. This direction is indicated 

 by the regular stratification of the slate and greywacke. 

 The same appearances are exhibited to the north of Cordova 

 in the hills which lie on the frontier of Portugal, to the 

 west of Albuquerque, but there, regularity is in many places 

 interrupted by more recent dislocations. An elevation pos- 

 terior to the deposition of the coal appears to have passed 

 from east to west 72° north, and presents itself regularly in 

 the chain of Solana, in the country of Montanches in the 

 Sierra de San Servan, in the neighbourhood of Pedroso, 

 and in the coal formation of Villa Nueva del Rio. 



The revolution which has followed the third tertiary 

 period, from east 17° north to west 17° south, is clearly 

 indicated by the course of the rivers Duero, Tagus, Gua- 

 diana, and Guadalquiver. It is a remarkable fact, that 

 some of the fissures which contain the mercury of Almadcn 

 follow the same direction as the hills in which they are 

 situated. The author considers, that the production of 

 these veins was contemporaneous with that of the ophites, 

 which is confirmed by the circumstance of round masses 

 of ophite being occasionally found in the cinnabar. It has 

 been long thought that mercury was a recent formation, 

 but the facts here stated shew that its origin is more 

 modern than geologists had ever conceived. In comparing 

 Estramadura with the rest of Spain, M. Le Play considers 

 that the revolution which occurred after the first transition 

 period, originated the rocks of Almaden, the eastern part 

 of the Pyrenees by Castres and Carcassone, the Sierras 

 D'Albarracin and Molina, as well as the granite and old 

 stratified rocks, extending between Cape Ortegal and Cape 

 Finisterre. These all extend east 40° north. 



After the second transition era, a revolution running 

 west 12° north, affected the whole of Spain, elevating the 

 Pyrenees in Asturia, the modern transition portion of 

 Estramadura, and probably, also the whole country between 

 the Tagus and Guadalquiver. To the south, it produced 

 also the Alpujarras, the Contraviesa, the Sierra de Lujar, 

 and all the mountainous country between Malaga and 

 Almeria. If a line be drawn through the small hills which 

 form the eastern part of the Sierra de San Servan, it will 



