498 Notes on the Pyrenees. 



under the name of Pic d'Anethou. This hitter does not form 

 part of the crest of the principal chain, but is situated at the 

 origin of a valley. 



Coursing to the west-north-west, the crest leaves the cul- 

 minating point of Mont Perdu to the south, and the Pic du midi 

 d'Assau, Neouvielle, and Vigne Mali to the north, presenting 

 at the appearance of the overlying alpine limestone accidents 

 which give rise to the most striking and beautiful scenery. 

 Beyond the Pic du midi d' Assau, the transition rocks are suc- 

 ceeded by the old red sandstone, which, alternating for short 

 spaces with the former, continues to nearly the western oceanic 

 extremity of the chain. The crystalline rocks are not thus 

 found constituting the greater portion of the crest, nor do 

 they in those points attain an elevation much exceeding that 

 of the transition or secondary series. The alpine limestone in 

 the north-east of the chain constitutes a series of parallel chains, 

 continued to the Montague de Corbieres, where it is suc- 

 ceeded by clay slate and greywacke, by which the crest is con- 

 tinued ; while it forms a series of transverse chains, met with 

 again lying at the extremities of the transition rocks ; the 

 band of the latter reposing on granite mountains reappears 

 on the other side, to form the crest of the principal chain. By 

 this disposition, the Pyrenees represent in their eastern por- 

 tion three different chains, in which the band of transition 

 rocks, forming the line of the principal crest, predominates 

 over the crystalline series, lying at some distance to the north- 

 east, or in the direction from which the waters should have 

 effected the degradation of the first series. 



In all cases, if we proceed by describing the variety in con- 

 stitution, or of combination, in each separate protuberance, to 

 give an idea of the geognostic stratum of a chain of hills or 

 mountains, we shall arrive at but an imperfect notion, even 

 when accompanied with the most minute details. Taking, 

 however, in view the physical character of the range, with the 

 general principles of its internal constitution, we can, by tracing 

 the elements of the disposition and accidents of the former, in 

 the deposition and developement of its mineral constituents, 

 ally in our description phenomena which are never separated 

 in nature, and deduce some general notions on the origin of 

 the mineral masses. For the variety which the same mineral 

 constituents are capable of assuming in their combination, 

 renders it both a tedious and useless task to pursue such inves- 

 tigations to their ultimate point : but the disposition which the 

 same minerals assume with respect to their geognostic super- 

 positions, or to their geographical distribution, is of the utmost 

 importance in deductions from the physical characters ofageo- 



