By the first of these ports Hannibal crossed from Spain on his way to Italy; by it also poured the Saracens to devastate the fields of Gaul. By Roncevaux Charles the Great passed to menace the Saracen power, and on his return met there with disaster at the hands of the Basques, which has been immortalized in song. East and west were debatable lands. Navarre sat astride on the ridge, with a foot in Spain and the other in Gascony. To the east was Roussillon, that pertained to the kings of Aragon, till ceded definitely to France in 1659. [Illustration: NATIVES OF ROUSSILLON] But to revert to the geological structure of the Pyrenees. The central chain is, as already said, composed of crystalline rocks, granite, and micaceous schist, whereas the northern chain exhibits the upturned beds of superincumbent deposits, and on the Spanish side the limestone lies on the granite. In the department of Haute Garonne the chains are soldered together by a transverse bar of mountain. J. H. Michon, author of _Le Maudit_, says well:-- “These mountains reveal to me almost the entire history of the successive periods in the terrestrial crust. I have but to follow the torrent of the Arbouste, and mount to the Lac de Seculéjo, and push farther to the Pic d’Espingo, to find myself on the crest of the ridge dividing France from Spain. Often at these altitudes, reaching to 3000 metres above the sea, the prodigious force which has rent the terrestrial crust in a fault of eighty leagues in breadth, which has upheaved, as in the Marboré, enormous masses of limestone that once formed the basin of seas succeeding each other at different epochs--often has this phenomenon filled me with amazement. There in the Marboré lie the beds, retaining their horizontality, as though the aqueous deposits had been formed at this great elevation. “But more commonly the central chain presents to our view masses of granite of astounding thickness. What a terrible cataclysm must that have been which thus reft and upset the globe, changing an extensive plain long submerged into a gigantic wall of granite shielded right and left with encasing masses of sedimentary formations which the upheaved granite has split and displaced in all directions.”