There was nothing for it, then, but a twenty-mile walk due west across the Causse Larzac by night to Tournemire, where one could get trains in any one of four directions. Constraint marked that last dinner with Eve de Montalais. They were alone. Louise was dining by the bedside of Madame de Sévénié, who remained indisposed, a shade more so than yesterday.

A little to the east, beyond the valley of the Cernon, which I intended to cross, were high hills or cliffs, treeless and sterile, with hard-cut angular sides, terminating upwards in vertical walls of naked stone. These were the buttresses of the Causse de Larzac. The lower sides of some of the hills were blue with lias marl, and wherever they were steep not a blade of grass grew.

The aridity, the absolutely waterless condition of the Larzac, has evolved a race of non-drinking animals. The sheep browsing the fragrant herbs of these plateaux have altogether unlearned the habit of drinking, whilst the cows drink very little. The much-esteemed Roquefort cheese is made from ewes' milk, the non-drinking ewes of the Larzac.

On the Causse de Larzac is Navacelles, in Gard; you walk over the arid plain with nothing in sight; and all at once are brought to a standstill. You find yourself at the edge of a crater 965 feet deep, the sides in most places precipitous, and the bottom is reached only by a zig-zag path. In the face of one of the cliffs is the grotto of Blandas, that has been occupied since remote ages.

I was on the border of the Causse de Larzac, one of the highest, most extensive, and hopelessly barren of the calcareous deserts which separate the rivers in this part of France. Not a drop of water, save what may have been collected in tanks for the use of sheep, and the few human beings who eke out an existence there, is to be found upon them.

Within a few yards of the Hotel Flouron we reach the edge of this escarpment, and gaze upon the wide valley of the Aveyron, village-crested hills, and the dim blue outline of the far-off Larzac. From the public promenade at the other end of the city we look westward upon a richly-cultivated plain set round with the Cantal mountains, gold-green vineyards, wine-red soil, and deep purple distance.

Hereabouts the barren, stony, wilderness-like country betokens the region of the Causses. We are all this time winding round the rampart like walls of the great Causse de Larzac, which stretches from Le Vigan to Millau, rising to a height of 2,624 feet above the sea-level, and covering an area of nearly a hundred square miles. This Causse affords some interesting facts for evolutionists.

Penetrating the upper valley of the Cernon, the railroad skirted the southern boundary of the Causse Larzac, then laboriously climbed up to the plateau itself; and Lanyard roused to the fact that he was approaching familiar ground from a new angle: the next stop would be Combe-Redonde. The day was still in its infancy when that halt was made.

Then Duchemin committed his second error of judgment, which consisted in thinking to find better and cooler air on the heights of the Causse Larzac, across the river, together with a shorter way to Nant indicated on the pocket-map as a by-road running in a tolerably direct line across the plateau than that which followed the windings of the stream.

If the reader now turns to a map of France, and draws a perpendicular line from Mende to Lodeve, and a vertical line from Millau to Florac, he will have a pretty good notion of the area occupied by the Causses, including that of the Larzac in Aveyron.