Towards the Gulf of Gascony the Pyrenees send out their ramifications in much gentler slopes than on the Mediterranean side. Forests and pastures are more profuse and luxuriant, but the peaks are still of granite, as they mostly are throughout the range. Grouped along the flanks of the river Bidassoa this section of the chain is known to geographers as the "Montagnes du pays Basque." At the foot of these Basque Mountains passes the lowest level route between France and Spain,--that followed by the railway and the "Route Internationale, Paris-Madrid." This easy and commodious passage of the Pyrenees has ever been the theatre of the chief struggles between the peoples of the Spanish peninsula and France. At Ronçevaux the rear-guard of the army of Charlemagne--"his paladins and peers"--were destroyed in 778, and it was here that the French and Spanish fought in 1794 and 1813. The French slopes of the Pyrenees belong almost wholly to the basin or watershed of the Garonne, one of the four great waterways of France, the other three being the Loire, the Seine and the Rhône. In the upper valley of the Garonne is the Plateau de Lannemazan. It lies in reality between the Garonne and the Adour. The Adour on the west and the Tech on the east, with their tributaries, play an important part in draining off the waters from the mountain sources, but they are entirely overshadowed by the Garonne, which, rising in Spain, in the Val d'Aran, flows six hundred and five kilometres before reaching salt water below Bordeaux, through its estuary the Gironde. Nearly five hundred kilometres of this length are navigable, and the economic value of this river to Agen, Montauban and Toulouse is very great. Between the Adour and the Gironde lies that weird morass-like region of the Landes, once peopled only by sheep-herders on stilts and by charcoal-burners, but now producing a quantity of resin and pine which is making the whole region prosperous and content. The source of the Garonne is at an altitude of nearly two thousand metres, and is virtually a cascade. Another tiny source, known as the Garonne-Oriental, swells the flood of the parent stream by flowing into it just below St. Gaudens, the nearest "big town" of France to the Spanish frontier. The Ariège is the only really important tributary entering the Garonne from the region of the Pyrenees. Its length is a hundred and fifty-seven kilometres, and its source is on the Pic Nègre, at an altitude of two thousand metres, three kilometres from the frontier, but on French soil. It waters two important cities of the Comté de Foix, the capital Foix and Pamiers.