188 



KNOWLEDGE. 



[August 1, 1900. 



For a picture of mediseval France, with its Roman 

 foundations and feudal superstructure, there is nothing 

 finer than Carcassonne, the old town still" cramped 

 within the ramparts, and the ville basse, or commercial 

 quarter, lying spread out in the plain below. The 

 narrow streets of the latter, by-the-by, were laid out in 

 the thirteenth century. 



Those who in this country could not gain the hciglits 

 walled themselves securely from attack in the alluvial 

 level. ]\Iirepoix, for instance, is boxed in like a 

 town of the Bavarian plateaux,* and the road now runs 

 round it, rather than enter the tiny gate, and pass, by 

 wooden arcades, beneath the burghers' houses. The fact 

 that, even at Carcassonne, horses are still fed in the 

 grassy intei-val between the outer and the inner wall, 

 shows how the country folk might find shelter in the 

 villes royahs, and serves to emphasise the parallel with 

 Bavaria. 



But here the essential feature is the enormous width 

 of the valley-floors, not the uniformity of the plateaux. 

 The lowland of the Garonne and its tributaries is 150 

 kilometres wide from the foothills of the Pyrenees to 

 Marmande; and it is 110 kilometres (more than 68 

 miles) from Pamiers, through Toulouse, to whore the 

 Aveyron leaves the Jurassic plateau in the north. This 

 country, so defined by nature, corresponds almost pre- 

 cisely to the Duchy of Gascony in the time of Charle- 

 magne, a well marked region, with the Pyrenees for its 

 southern march, and meeting Aquitaine along the line 

 of the Ariege and the Garonne. Whoever held the 

 passes of the Pyrenees almost held the heart of France. 

 In the eighth centui7, the Mohammedan wave, which 

 had submerged Carcassonne, isolated Toulouse, and 

 reached the Atlantic, following the courses of f.he 

 streams, surged even into the limestone plateaux, and 

 was checked only at Poitiers. It is interesting to note 

 how the central knot of granite, the countiy of 

 Clermont-Ferrand and the Cevennes, broke the strength 

 of the invasion, which ran up thence on either side, 

 and devastated Autun on the east. Almost in our own 

 time, the British forces, when once the Pyrenees nad 

 been rounded, pressed on from one stream to another to 

 the foot of the plateau at Montauban. 



This great plain of the Garonne, with the rivers 

 streaming from the Pyrenees, is one of the most striking 

 features of France, when viewed upon an ordinary maj?. 

 The radial arrangement of the watercourses from the 

 foothills near Bagneres de Bigorre makes the greater 

 part of the country look like one huge delta. Some 

 twenty of these streams are caught by the Adour, and 

 enter the Atlantic at Bayonne; another twenty escape 

 to the Garonne, and so are carried to the north. The 

 lower portions of the two groups thus enclose between 

 them the strange and wind-swept level of the Landes. 



The tributaries reaching the north bank of the 

 Garonne are far less neatly grouped, although some have 

 made adventurous journeys from the east. The broad 

 Gascon lowland has, indeed, received the waters from 

 the central plateau, from the great volcanic knot of 

 Aurillac, and from the bare limestone country of the 

 Causses, as well as the rapid drainage of the Pyrenees. In 

 Pliocene times, the elephants already found fccdiiig-room 

 in the Landes, and their remains became entombed in the 

 alluvial clays. The sands of the district have accumu- 

 lated since then, largely drifted from the Atlantic 

 dunes; and the changes in land-tenure in the present 

 century have led to a destraction of the forests, which 



* See " Contrasts in Bavaria," Enowlbdge, June, 19U0. 



alone held the soil together. The State has now been 

 compelled to step in, and to defend the peasantry 

 against themselves by a system of scientific planting. 

 The contrast between this shifting country and the 

 granite frontier of the Pyrenees is abrupt enough when 

 one looks southward; it is a picture in little of the 

 Himalayas and the alluvial plains of India. 



Even the yellow rocks which underlie the surface- 

 deposits, and which increase in antiquity as we trace 

 them to the east, are not older than those of our 

 London Basin. But the earliest among them have 

 witnessed the uplifting of the Pyrenees. The marine 

 fossils of the lower Eocene are included in the folds oi 

 the foothills at both ends of the chain ; the wai-m sea 

 of southern Europe once stretched across the site oi 

 the great ridges. Then the " Alpine " series of eartb- 

 movements set in beneath the whole of the European 

 area, and a long east^and-west fold heralded the birth 

 of the Pyrenees. The central mass beyond Bagneres de 

 Bigorre, to this day the " Hautes Pyrenees," formed an 

 island in Middle Eocene times,! ^^'id tlie southern tribu- 

 taries of the Garonne thus began to flow before the main 

 river was in existence. The relation is the same as that 

 between the Alpine tributaries of the Danube and the 

 Danube itself, which, when it came into being, caught 

 in the smaller streams and systematised them. 



The pebbles from the uprising Pyrenees now began to 

 be carried down, and to form beaches and deltas, in 

 which organic remains are rare. The whole floor of the 

 nummulitic sea became a lacustrine region, and the 

 marine beds cease with the close of Eocene times. Mire- 

 poix itself, between the limestone foothills and the 

 antique Montague Noire, stands upon freshwater strata 

 of the same age as those of Headon Hill in the Isle of 

 Wight. Our southern coast of England, with its marine 

 Eocene and fluviatile Oligocene strata, forms, indeed, 

 an interesting parallel v^^ith the laud of the Bastides. 

 The vertical and folded chalk of Freshwater Bay re- 

 presents the compacter Cretaceous limestones that lie 

 along the flanks of the Pyrenees; the period of its 

 uplift has been the same, and on its back we see the 

 gravels worn from it, covering the lacustrine strata to 

 the north, and reproducing the huge stream-deposits 

 which have spread into the plain of Gascony. 



The watershed between the Atlantic and the Mediter- 

 ranean, west of Castelnaudary, is only some 200 metres 

 above the sea. The easternmost tributaries of the 

 Garonne, reaching to Labastide-d'Anjou, have almost 

 touched the head-waters of the steeper Mediterranean 

 streams. This innocent and unnoticed pass has now 

 been traversed by a canal which is fed by the water 

 of both systems. The real features of the landscape 

 ai-e the valley-walls of the Fresquel, running eastward, 

 on a spur of which the bastide of Fanjeaux stands. 

 The parting-ground, however, seems to have been deter- 

 mined as far back as Oligocene times ; for the deposits 

 of that period, both cast and west of it, are of a fresh- 

 water and marshy nature. The submergence that 

 occurred in the Middle Miocene epoch admitted the sea 

 into the plain of Orleans, and far up the long depression 

 that now forms the valley of the Rhone ; but the bulge 

 at Castelnaudary held its own, and the Pyrenean earth- 

 movements were still making themselves felt beneath 

 it. By Pliocene times, the whole lowland from Nar- 

 bonne to Bayonne had been brought above the sea ; 

 the desolate Landes had made their appearance, a de- 

 bating-ground for rivers and the Atlantic; and the 



+ See Be Lapparent, " Traite de Geologie," 4me ed. (1900), p. 1433. 



