Page:A book of the Pyrenees.djvu/19

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5
WATERSHED

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."

To the north of the Pyrenees lies a deep trough extending from the Bay of Biscay to the Corbières that links the Pyrenees to the Cevennes, and which at the present day forms the watershed between the Mediterranean and the Atlantic. This gulf was gradually silted up by the torrents from the Pyrenees. Masses of rubble may be seen backing and capping isolated hills of sandstone, and forming long ridges, as that of the Park at Pau. The drift was from east to west. All the low hills are crowned with rolled stones. The boulders