After proceeding about a league and a half, a blast came booming from the north, rolling before it immense clouds of dust; happily it did not blow in our faces, or it would have been difficult to proceed, so great was its violence. We had left the road in order to take advantage of one of those short cuts, which, though possible for a horse or a mule, are far too rough to permit any species of carriage to travel along them. We were in the midst of sands, brushwood, and huge pieces of rock, which thickly studded the ground. These are the stones which form the sierras of Spain and Portugal; those singular mountains which rise in naked horridness, like the ribs of some mighty carcass from which the flesh has been torn. Many of these stones, or rocks, grew out of the earth, and many lay on its surface unattached, perhaps wrested from their bed by the waters of the deluge. Whilst toiling along these wild wastes, I observed, a little way to my left, a pile of stones of rather a singular appearance, and rode up to it. It was a druidical altar, and the most perfect and beautiful one of the kind which I had ever seen. It was circular, and consisted of stones immensely large and heavy at the bottom, which towards the top became thinner and thinner, having been fashioned by the hand of art to something of the shape of scollop shells. These were surmounted by a very large flat stone, which slanted down towards the south, where was a door. Three or four individuals might have taken shelter within the interior, in which was growing a small thorn tree.