Notes on 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- 
tinued 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 may be 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 1600 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 Amé Boué 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 gradationas 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 1500toises; 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 
