Okay for mapping, but useless for anything else.”
“Like what?”
“You know as well as I do what kind of things show up well from the air. Evidence of cultural interference. Archaeological sites and records of natural disasters. Wherever the vegetation changes its color or its pattern because the soil has been turned over or otherwise altered.”
“There are plenty of natural disasters hereabouts,” I commented. “But the eruption record of the volcanoes isn’t likely to worry them much. Vegetation shadows of archaeological sites...but the aliens never built so much as a mud hut, so far as we know.”
“So far as we know,” he echoed.
“But now they’re enslaved, and they live in little round tents. In the wild, they were pre-cultural. No language beyond a range of animal grunts. No permanent tools. No fire. But they’ve adapted now, very quickly and very well.”
“If you’d built a culture based on the services of adaptable, docile aliens, and had spread yourself very thin across two continents, and you were outnumbered by several hundred to one by your slave-race...mightn’t you begin to wonder? Mightn’t a little anxiety creep in, slowly and insidiously?”
“Vegetation shadows,” I repeated, letting my imagination roam. “I didn’t see anything...and why here, of all places? This is the last place on the continent to look for traces of a vanished civilization.”
He shrugged. “So maybe it’s the Fountain of Youth,” he said.
We set off again, setting a steady, sensible pace. As we descended into the valley toward the stream that ran across the shallow bowl the going got a little tougher because of the more abundant vegetation, especially the thorny creepers. But there were always expanses of bare rock and thin grass, and it was easy enough to find a route that didn’t take us far off the straight course we’d plotted out for ourselves. Farther down we even spotted a small herd of wild donkeys—perhaps twenty or twenty-five strong—grazing on the slope. They moved off while we were still a couple of hundred meters distant, and I had a brief pang of regret regarding my lost binoculars, but it soon passed. They were, of course, a native life form, but they could actually have passed for Earthly donkeys in a dim light. They were ready-made pack animals, though they walked a little slowly to be ideal as riding animals, except where the terrain was really rough.
Once a bird of prey swooped across the scrub a short distance ahead of us, in pursuit of some small creature, but it must have reached its bolt-hole. The bird soared up into the sky again, empty-clawed. Half an hour later I saw it swoop again, but this time another bird went for the same target and they ended up having a go at one another instead, cawing madly. A couple of dark feathers fluttered to the ground before they went their separate ways. It looked like a lean day for them so far—but they had lots of time. A hawk has only to be patient, because it usually wins in the end. The creatures on the ground have to go about their own business, taking their daily risks and hoping at best to survive. But nothing bothers the hawk up in the sky.
There were trees here, but they clustered in patches of ten or a dozen, and for the most part they were weedy specimens, with tall thin trunks extending eight or ten feet up and then spreading out clusters of branches like the kind of imitation bouquets that conjurors produce from their wands. The soil up here grew deep in grooves where wind and weather had eroded the lava which had spilled out of the ground long, long ago, but there was always more wind and more weather, and the bedrock was too close to the surface. The vegetation pattern here must change with the decades. Only permanent soil holds shadows. If that was really what Mme. Levasseur hoped to see, she’d have to look at valleys deeper and steeper than this great saucer we were crossing now.
We came to a region where the thorn sprays formed great carpets, looking for all the world like brownish lakes with waves and whirlpools. Most of the foliage hereabouts was brown or gray-green, and all in darker shades.
We had to stop again soon. We were having trouble with the air, which was thinner than we were accustomed to. I had prescribed carbon pills before we set off, and had packed a couple of the oxygen-bottles that we could use if need be, in association with sterile suits should their filters be faced with an impossible job, but we had to use the oxygen sparingly, and it really offered only temporary relief. The carbon pills had little enough effect—I’d never really believed in them on Earth, on the occasions when I’d had to do high-altitude work. If anything were to stop us getting to the crater in one day it was surely going to be the atmospheric pressure.
We tramped on across a wasteland of grass-knotted gravel that lasted for three or four miles, and finally got to the bottom of the saucer, where the thickness of the vegetation finally got to the point where it might impede us. But there was little enough of the thorny stuff here—much of the plant life consisted of brittle-stemmed things like ferns and small flowering plants. We found that the only significant nuisance was caused by tiny insects which settled on our faces and the backs of our hands—attracted perhaps by the moisture or the salt in our sweat. They didn’t bite, but one or two of the species apparently went through life secreting or excreting some irritant substance that made us itch.
We found numerous small pools where the water of melted snows or spring rains had collected—some of them quite deep and obviously permanent. They tended to be long and narrow, often curved into thin crescents. The water was murky and rather foul in the small pools, and even the larger ones had a scum of vegetable debris and skimming creatures that might have been larvae of one kind and another. I saw water snails and rafts of eggs and shrimp-like invertebrates. We filtered some water and boiled it to replenish our own supply late in the morning, though it wasn’t necessary. It just gave us something to do while we were taking it easy. I calculated how far we’d come and found we were only a few minutes behind schedule.
“They’re always the same,” said Nathan, who was watching a small flock of birds in the branches of a tree growing by the bank of the pool. “On every world we go to. The plants are different, to some extent, but not the birds. Even large animals are sometimes quite bizarre, but the birds are always the same. It almost asks you to believe that there’s a pattern in it all somewhere. When you come down to it, the differences in the intelligent forms are more striking than the similarities...especially with the species like the salamen. But you can always find sparrows made in the image of sparrows on Earth. Maybe God’s a sparrow.”
“Whenever different cultures invent certain things they do it the same way,” I pointed out. “Whether it’s made by human or alien a wheel is always round. A bow and arrow is always a bow and arrow—even quite complicated things like saddles are made to fit an animal’s back one way and a human arse the other. An organism is a kind of technology too. It’s an egg’s way of making another egg. All eggs look pretty much the same—they’re either round or egg shaped. The ways they have of reproducing themselves are pretty much akin, too. An organism is a device; an invention. There are certain forms which are up to the job, and some that are capable of a certain amount of variability on a basic theme. Birds are one of the possibilities where there’s relatively little variation possible, and where virtually every possibility tends to be worked out in any one life system. Flying’s a good trick. It usually makes for evolutionary security, so what variation there is tends to come out. See?”
“I think so,” he replied.
“In the whole of evolutionary history here and on all the Earth-type worlds we’ve tried to colonize eggs have made exactly two vital inventions,” I went on. “The eggshell and the womb. All else is variation on a very few anatomical themes. You could count the internal skeleton as well, I guess, but on some worlds that are pretty far removed from the Earth model but still hospitable enough for us to investigate, animal life has got along without that particular invention. It still developed shelled eggs and
