380 NATURAL SCIENCE. June, 



the causses, which it took countless ages to accumulate, and land that 

 once maintained a well-to-do population is reduced to a desert." 



"Swept by the cold winds of winter and parched by the heats of 

 summer, only a Caussenard," says Reclus, "can love the causses, but 

 every citizen of the world can admire the gorges of mighty depth that 

 cleave it, and the precipices that form the walls of this gigantic 

 acropolis. In decending by goat paths these bordering precipices, 

 one is suddenly transported from parched wastes to pleasant pastures, 

 from vast horizons, vague in outline and sad in tone, to smiling nooks 

 of blended Heaven and earth . . . The startling contrasts between 

 some of the canons and their causses form one of the most pheno- 

 menal beauties of beautiful France." 



But the pleasant pastures are generally very small, and the 

 smiling nooks are often perched on steep slopes or on a narrow ledge 

 above the rushing river. One or two of these gorges are indeed wide 

 enough to admit of river, road, and rail ; but most of them are in 

 places so narrow that the river washes precipitous cliffs on each side. 



It is these deep ravines or canons, with their vertical walls, 

 rising sometimes in a single sheer, continuous cliff, sometimes in a 

 series of steps, with mural scarps and faces, that are the distinctive 

 feature of the causses country. The tableland is divided by them into 

 a number of isolated masses, and it is impossible to pass from one 

 causse to another without descending into the depths of the canon, 

 and climbing again up the opposite cliff; there is no way round, for 

 the river enters the caiion between limestone walls, and completely 

 traverses the limestone region. 



The average depth of these chasms is from 1,300 to 1,500 feet, 

 and their width at the bottom varies from 160 to 1,500 feet. Their 

 rocky walls are carved by rain and frost into an infinite variety of 

 buttresses and turrets, alcoves and recesses, which recall the fantastic 

 conceptions of Gustave Dore. Still, there is nothing monotonous or 

 sombre about the scenery of the canons, for though in places their 

 precipitous sides close in till there is only just room for the river to 

 pass, yet soon they widen out again and give space for fields and 

 vineyards and orchards. 



The finest of the canons is that of the Tarn. " The whole of its 

 course," writes Mr. Baring-Gould, " from Ispagnac to Roziers, a 

 distance of thirty miles, is one succession of marvels. At every turn 

 comes a surprise. The forms of the rocks are not alone singular and 

 beautiful, the colouring is rich as it is surprising. The dolomitic 

 limestone, which rises in nakedness to the height of 600 feet and even 

 1,800 feet on each side of the water is tinged and splashed with 

 colour. It is fawn or salmon colour, with patches of red ochre, here 

 stained black, there it gleams white. Everywhere it is sprinkled with 

 the green of the box and the juniper clinging to the interstices. 

 Overhead gleams down the azure sky and below flashes the foaming 

 river." (Op. cit., p. 80.) 



