Plan B.
The simplest scheme, then, in which we can regard the Pyrenees, is as a system of not quite parallel lines of equal length, running one towards the other, but missing by not quite 8 miles; the gap or “fault” joined by a zigzag saddle on the watershed. The westernmost of these lines splits into several branches before it reaches the Atlantic, so that the true western end of the chain lies well to the south and east of that ocean (at Mount Urtioga); the other starts from, and forms a projection in, the Mediterranean. The full distance as the crow flies from Mount Urtioga to Cape Cerberus upon the Mediterranean is 390 kilometres, that is 241 miles. And there is but 10 kilometres, or 6½ miles, difference in length between the two halves of the chain.
If U be the point called Mount Urtioga, S the Sabouredo, L the Pic-de-l’homme, and C Cape Cerberus, these two lines and the gap between them will lie precisely as in this plan.
With this main guide by which to judge the structure of the chain, all details will be found to fit in, and the two first variations which we must superimpose upon so general a view, are to be found in the “step” or “corner” formed by the watershed round the Pic d’Anie. The southward turn of the range is here not gradual but sharp, and the Somport, the pass at the head of the Val d’Aspe, lies almost a day’s going below the Port St. Engrace, which is the Pass near the Pic d’Anie. Next, one should note the two re-entrant angles, one to the north of the chain, one to the south, which distinguish the Spanish valley of the Gallego and the French valley of the Gave de Pau respectively. These features modify the simplicity of the first or western branch of the chain; one exceptional feature only modifies the second or Eastern branch, and this is the deep re-entrant wedge of the Ariège valley upon the French side. We may therefore regard the elements of the watershed somewhat according to the sketch plan B on the preceding page.
Plan C.