Notes 071 the Pyrenees, 497 



too general views of those who suppose a junction of the 

 Pyrenees, whether with the Alps or the Cevennes, through 

 the medium of the " montagne noire." To the south we 

 have not had sufficient opportunities of observation to give any 

 determinate opinion. M. Charpentier states that it is con^ 

 tinned as far as Cape Ortegal, in Galicia. The limits may 

 be considered as marked in the north by the superposition of 

 the tertiary formations ; to the south they have not been 

 determined. Its length, as extending only from ocean to sea, 

 does not exceed five degrees of longitude ; its breadth vary- 

 ing throughout with the extent of the transverse chains. The 

 quantity of surface which it maybe supposed to occupy has been 

 estimated at 198 square leagues. In its central part, a solution 

 of immediate continuity takes place, and a divergence from a 

 straight line ; its western acclivity receding 1 600 toises to the 

 south, but in the same direction as the eastern acclivity. The 

 general direction of the chain, with respect to the meridian, 

 is constantly from east-south-east to west-south-west, and that 

 of the strata is most generally the same. In investigating their 

 structure, the Pyrenees appear to consist of a series of bands 

 of alpine limestone, old red sandstone, and transition rocks, 

 reposing alternately on mica slate, or granite, or a mass of 

 intermediary rocks, locked here and there in stratified crys- 

 talline beds. The gneiss and mica slate, generally feldspathic, 

 are, on the one hand, so intimately connected with the transi- 

 tion series, that Ame Boue did not think that their separation 

 was possible ; while their intimate relation with the crystal- 

 line deposits, and the accidents of the latter, led him to suspect 

 that these were most probably of a date posterior to that of 

 gneiss. M. Charpentier, considering the crystalline primitive 

 rocks to join the base of the chain, supposes a gradation as marked 

 by the succession of primitive, transition, and secondary rocks ; 

 and, to account for their degradation and frequent absence on 

 the Spanish side, gives an ancient hypothetical section, by 

 which the culminating point of the crystalline mass being car- 

 ried away with the other formations to the south, leaves the 

 transition and secondary rocks predominating on the chain. 



The crystalline rocks never attain in the east an elevation 

 equal to 1500 toises; while the transition series, succeeding im- 

 mediately in the continuation of the crest, rise to an elevation 

 exceeding that sum, and continue, without interruption, to the 

 Port de Glare, where the former again form the crest of the 

 chain. The elevation of the latter is here at its maximum ; 

 but the culminating point of the Pyrenees, ascertained by the 

 geodesical operations of MM. Reboul and Vidal to be not the 

 Mont Perdu, but the easterly peak of the Maladetta, known 



