They passed, and we reentered volcanic ground. Little pimply craters stood about, often two or three together, and from them spines of high, broken basalt led down like disordered causeways across the barren ridges; but these craters looked old, not sharp and well-kept like those of Ras Gara, near Wadi Ais, but worn and degraded, sometimes nearly to surface level by a great bay broken into their central hollow. The basalt which ran out from them was a coarse bubbled rock, like Syrian dolerite. The sand-laden winds had ground its exposed surfaces to a pitted smoothness like orange-rind, and the sunlight had faded out its blue to a hopeless grey.