Going on again presently, our whole attention becomes absorbed by the new and singular geological features of the Libyan desert. A vast plain covered with isolated mountains of volcanic structure, it looks like some strange transformation of the Puy de Dôme plateau, with all its wind-swept pastures turned to sand and its grassy craters stripped to barrenness. The more this plain widens out before our eyes, the more it bristles with peaks. As we round the corner, and Dakkeh, like a smaller Edfû, comes into sight upon the western bank, the whole desert on that side, as far as the eye can see, presents the unmistakable aspect of one vast field of volcanoes. As in Auvergne, these cones are of all sizes and heights; some low and rounded, like mere bubbles that have cooled without bursting; others ranging apparently from one thousand to fifteen hundred feet in height. The broken craters of several are plainly distinguishable by the help of a field-glass. One in particular is so like our old friend the Puy de Pariou that in a mere black-and-white sketch the one might readily be mistaken for the other. We were surprised to find no account of the geology of this district in any of our books. Murray and Wilkinson pass it in silence; and writers of travels--one or two of whom notice only the “pyramidal” shape of the hills--are for the most part content to do likewise. None seem to have observed their obvious volcanic origin. Thanks to a light breeze that sprang up in the afternoon, we were able to hoist our big sail again and to relieve the men from tracking. Thus we glided past the ruins of Maharrakeh, which, seen from the river, looked like a Greek portico set in a hollow waste of burning desert. Next came Wady Sabooah, a temple half-buried in sand, near which we met a tiny dahabeeyah, manned by two Nubians and flying the star and crescent. A shabby government inspector, in European dress and a fez, lay smoking on a mat outside his cabin door; while from a spar overhead there hung a mighty crocodile. The monster was of a greenish-brown color and measured at least sixteen feet from head to tail. His jaws yawned; and one flat and flabby arm and ponderous paw swung with the motion of the boat, looking horribly human. The painter, with an eye to foregrounds, made a bid for him on the spot; but the shabby inspector was not to be moved by considerations of gain. He preferred his crocodile to infidel gold, and scarcely deigned even to reply to the offer.