498 Notes on the Pyrenees. 
under the name of Pic d’Anethou. This latter 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 i in 
the north-east of the chain constitutes a series of parallel chains, 
continued to the Montagne de Corbicres, where it is suc- 
ceeded by clay slate and greywe acke, 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 distanue 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 
co) 
mmportance in deductions ; from the physical characters ofa geo- 
