The Alien Intelligence by Jack Williamson

For a long, long time I gazed into the abyss, lost in the wonder and the mystery of it. Meanwhile the sun climbed over and lit the farther rim, which still was black or dully red, because of the dark colors of the volcanic rocks of which it is composed. The scene was so vast, so strange, so wildly beautiful and unearthly, that it seemed almost a dream, instead of an ominous reality. It was hard to realize that somewhere upon the red plain, or along the shores of the Silver Lake, or perhaps beneath the banks of mist beyond, Austen was -- or had been -- alone, and in distress. I wondered, too, from what part of this strange world had come the thing of the whistling sound and the red light, which had taken the ponies.

It was well after noon before I ate a little lunch and took thought of the matter of descent. I saw that a second ladder led down in a fine line of silver until it disappeared above the crimson upland, miles below. I climbed over the brink and started down. Descending was easier than climbing had been, but I had infinitely farther to go. The soles of my shoes were cut through, and my hands became red and blistered on the rungs. Sometimes, when I was too tired to go on, I slung myself to the ladder with a piece of rope from my pack, while I rested.