Cycle of Fire

XII. GEOLOGY; ARCHAEOLOGY

ABYORMEN IS larger than the earth and has a smaller percentage of sea area even in the cold time, so the geologists had a great deal of territory to cover. They did not, of course, attempt to do it all; the basic plan was to attempt enough stratigraphic correlation to get a fair idea of its geological history and, if at all possible, find datable radio-actives in the series far enough down to get at least a minimum value for the age of the planet. The last was all the astronomers really wanted, but the biologists had considerably higher standards. They came along, prepared to analyze any fossils found by every technique known to their field.

Layer after layer of sedimentary rock was traced, sometimes for miles underground, sometimes only yards before it vanished — perhaps because quakes had shuffled it into a puzzle that took experience to solve, perhaps because the phenomena which had deposited it in the first place had covered only a limited area and the formation pinched out naturally. A limestone bed laid down over a million square miles at the bottom of a sea is one thing; a sandstone lens that was once the delta of a stream running into a small lake is something else — sometimes a rather inconvenient something else, when a problem of relative dates is in question.

Kruger thanked his luck that Commander Burke was not with this ground party and prayed constantly that he would not overhear any remarks made by the geologists, for Dar Lang Ahn was learning a good deal of English as time went on, and there are few places where a photographic memory can make itself more obvious or useful than in a stratigraphy problem. The geologists without exception regarded the native with awe and felt a friendship for him comparing strongly with Kruger’s own. Sooner or later the commander would learn; the boy hoped that by then his little friend’s popularity would have reached a point where the old officer would be moved to get rid of his suspicions.

Nowhere on the planet did there seem to be structures corresponding with the “shields” which characterize certain parts of Earth. Apparently all the present land surface had been submerged in the not too distant past; there was more than a suggestion that Abyormen suffered much more seismic and orogenic activity than Earth. One of the specialists suggested that a reason for this might lie in the “Long Year” seasonal changes, when the greater part of the sea water was deposited on the ice caps. A seismic check of the cap in the southern hemisphere (not over the south pole) indicated a thickness of nearly thirty-five thousand feet. It was snowing at the time the check was made, Theer never shone on this part of the planet, and Arren would not rise for several terrestrial years.

While several of Abyormen’s short years passed before any absolute dating of strata was possible, the astronomers learned what they had feared rather quickly. From the beginning, of course, the geologists had kept their eyes open for pegmatites and other igneous intrusions which might contain radioactives suitable for dating, and fairly soon these were found at several places on the continent they were examining. It was not possible to correlate these rocks with the sedimentaries, at the time, but one of them had a uranium-lead ratio corresponding to an age of just under one and a half billion years. It was a large sample, and ten independent checks were run, none varying more than about twenty million years from the mean. Since the astronomers were not willing to believe that Alcyone had been in existence longer than something like one per cent of that time they accepted the information a trifle glumly.

But dated or not, the sedimentaries had their own fields of interest. If Dar Lang Ahn had ever seen a fossil in his life he had never given it a second thought. This omission was easily remedied, for the sediments had their share of organic remains. A lens of limestone some two hundred miles across, near the center of the continent, seemed to consist largely of a reef deposit, and several hundred different species were found at various points within it. Shellfish that might have come straight from Earth were present by the thousands — at least, so it appeared to Kruger; a biologist spent much time pointing out technical differences.

“I suppose,” he finished, “that you could find a good many creatures virtually identical with these on the shores of your present oceans. There seems to be some ability in the mollusks and their relatives to ride out the changes of a planet. On Earth they’ve been around for half a billion years — changed, to be sure, but the basic plan seems to keep right on going.”

“I understand you in all but one point,” Dar Lang Ahn replied in his slow, careful English. “I have been with you all along here, and have seen fossils like this in many different layers of rock, as you say is reasonable, but I have never seen a living creature which in any way resembles those fossils.”

“Have you ever spent any length of time at the seashore?”

“Much. Nils Kruger and I walked along one for about three hundred miles recently, if the occasions in my previous eight hundred years don’t count.”

“That’s right!” Kruger exclaimed excitedly. “I knew there was something funny about that beach and never could put my finger on it. There weren’t any seashells, or stranded jellyfish, or anything of that nature. No wonder it looked queer!”

“Hmph. I confess that is distinctly odd. How about other sea creatures?”

“I don’t know. I think there are animals of various sorts living in the water, and I’m sure there are plants. I can’t think of very many different kinds, though.” The biologist gave this bit of information to those of his colleagues engaged in field work; he himself was too busy with fossil correlation to follow it up.

Gradually he established order out of the chaos. For purposes of discussion, he divided Abyormen’s past into periods whose boundaries in time seemed to have been established by the general flooding of this continent which had resulted in the limestone beds. The geologists could not find evidence for definite periods of mountain-building, which are usually better for such a purpose; on Abyormen, as they had already suspected, orogenic activity seemed to be fairly uniformly distributed through time.

There were, of course, many reasons why the world might be more active seismically than Earth. It was larger, for one thing — ninety-one hundred miles in diameter and forty per cent more massive, so that a one hundred seventy pound man weighed about one hundred eighty on its surface. The percentage difference was small, but the total tonnage of gravitational forces available for orogeny was much larger than on mankind’s home world. At any rate there was the evidence — mountain-building periods were short, frequent, and local.

This should have made the biology department happy, even though it promised trouble for the astronomers. Unfortunately the vertebrate fossils had produced another headache.

It had not proved difficult to set up a general sequence almost certainly corresponding to the course of evolution on the planet, spanning what must have been several hundred million years, if Earth could serve as an example. This sequence started with things just barely possessed of hard-enough interior parts to preserve, ran through bony creatures comparable to the fishes, and led eventually to legged creatures which quite obviously breathed air and spent their lives, or most of them, on dry land. It would have been nice to have been able to put the simple end of this series at the bottom of a page and Dar Lang Ahn at the top, with logically intermediate forms in between, but this was rendered impossible by the fact that every fossil vertebrate found that was possessed of bony limbs at all had six of them. Dar was sufficiently human to have two arms and two legs, with no visible trace of any others.

At the biologists’ urgent plea the native submitted to having a set of X-ray photographs made of himself. He was as interested as anyone in looking at the results, and was as able as any biologist to see that his skeleton bore no traces of a third pair of appendages.

Dar by now was as familiar with the general principles of evolution as the average educated human being and could see why the professionals were bothered. Even before anyone had asked he commented, “It looks as though nothing you’ve found in the rocks could be a direct ancestor of my race. I suppose we might have come from some other world, as Nils once thought, but there is nothing in any book I have ever read, or that any Teacher has ever told me, to suggest such a thing.”

“That spikes that one,” remarked the biologist sadly.

“Not entirely; it is quite possible that it happened so long ago that either we kept no records or they have been lost in the meantime. However, I’m afraid it will be a little difficult to prove.”

“You’re probably right. I think one thing that had better be done is to look for definitely recent formations.”

The geologists had listened to this conversation; it took place during one of the regular breaks for meals. One of them now spoke up.

“It’s a little hard to look at a formation casually and say, ‘this is less than a million years old.’ We’re keeping our eyes open, of course, but you know perfectly well that dating comes afterward — after excavation, and finding fossils and comparing them with other formations.”

“How about unconsolidated material on talus slopes or in caves?”

“Hardly our field, but we’ll bore into any we find. I’m not sure I recall any really well-developed cave country, though some of these limestone layers might furnish the makings if the climate cooperated.”

“I have heard of caves on some of the other continents in which strange diagrams and drawings could be seen on the walls,” offered Dar Lang Ahn. The party turned toward him as one.

“Can you take us there?” Several voices asked the question almost simultaneously.

“Maybe. It would be safer if we went to one of the cities on that continent and had one of the local people act as guide.”

So it was arranged, after consulting with Commander Burke on the distant Alphard. Another flier was sent down to take the small party, so that the geologists would not be deprived of a means of travel, and several more specialists came down with the new vessel.

The continent in question lay far to the south and west of the place where the work had been going on but was still under the light of red Theer. Dar Lang Ahn found a city without difficulty and, after the usual explanations which sight of the human beings required, was able to obtain a guide. Actually, many of the citizens chose to come along to see the strangers at work; there was little of importance to be done, since all the books of this particular city had been taken to the Ice Ramparts and the people were simply awaiting death.

The caves were precisely as Dar had described; there was no doubt in the minds of any of the men that they had been inhabited by beings in the dawn of a civilization. Most of the visitors were attracted by the pictures on the walls, which Dar had mentioned, but those who knew what they were doing set to work with extreme care on the floors.

These were covered with hard-packed earth, which was carefully removed, layer by layer, and sifted for anything that might be present. The natives commented freely on everything that came to light; they had never thought of digging there themselves and apparently did not recognize any of the objects that were found. These might just as well have come from a similar cavern on Earth — tools of stone and bone and objects which might have been ornaments.

For days the digging went on. The scientists had hoped in the beginning that skeletons of the inhabitants might turn up, but they were disappointed. One of them mentioned this to Dar.

“It’s not too surprising,” the native answered. “I can see that these people lived in a way different from ours, but it can’t have been that different. They either died at the proper time and left no trace, or died by violence, and that would hardly have happened in the caves here.”

“We don’t really know that it was people like yours who lived here,” answered one of the scientists drily. “Somewhere in the history of this planet of yours there seems to be a big break. I might have suspected that your people came from another planet and the ‘hot’ ones were native to Abyormen, if we didn’t know about the father-son relationship you have with them.”

“Perhaps we both did,” suggested Dar. The biologist brightened.

“That’s a possibility. I wish the people who lived in these caves had drawn a picture or two of themselves.”

“How do you know they didn’t?” The scientist looked up at the weird creatures whose images sprawled across the limestone walls and ceilings.

“I don’t,” he said sadly. “You would bring that up. At least none of them are six-limbed, which at least suggests the animal life at the time this cave was inhabited was more closely related to you than what we found in the rocks can have been.”

The scientist went back to his work, and Dar Lang Ahn, for the first time since Kruger had known him, went off by himself. He saw the boy looking after him and called back with his equivalent of a smile, “Don’t worry, I just want to be alone for a while. I have a lot of thinking to do. Don’t be afraid to call me if anything exciting happens.”

Kruger felt relieved but was not quite sure what would be listed as exciting by his little friend. At first, after the arrival of the Alphard, virtually everything had seemed to qualify; the native had difficulty in keeping his attention on one thing at a time, since everything in his vicinity demanded examination. As time went on that tendency had disappeared. Kruger wondered whether Dar could possibly be losing the interest in the sciences which the boy had been trying to develop. He decided that the risk was slight; this work was getting a trifle boring, even for Kruger. It had long since passed the point where every new fossil, flint knife, or piece of limestone added noticeably to their fund of knowledge.

He wondered whether it would be worth while to return to the Alphard with Dar to see what the astronomers were doing. It would be a change and if Dar’s interest really was flagging, unlikely as that seemed, it might take a new turn for the better. He would make the suggestion when Dar emerged from his contemplation.

It turned out that the little native was not tired of geology, however. His natural courtesy made him suggest that they go back to the other party for “just a little while” before returning to the ship; he would not have considered a return at all had he not realized that Kruger was getting bored.

The geology group, when they did get back to it, had made progress — more than they or anyone had a right to expect; so much that Kruger’s boredom disappeared within seconds after landing at the current site of operations. Briefly, they had found the “break” in the geological sequence.

It had dawned on one of the scientists, after much fruitless labor, that the drastic climatic change each long year should produce an effect similar to, but more pronounced than, the seasonal changes in such formations as varved clays on Earth. Lakes, for example, should dry up completely and alternate wind-blown with water-laid sediments in a much more distinct fashion than had ever been seen on the home planet. With this thought in mind they had selected a large, shallow lake. A series of cores from the edge compared with a similar series from the deepest part of the body of water had led to results which were fairly certain to make the astronomers very happy.

The seasonal changes as described by the Teacher in the distant village of the geysers had been going on, apparently, for just a trifle under six million years according to one worker’s theory, or a trifle over ten million according to another’s. The two schools of thought were about evenly divided, the first basing its figures on the assumption that the long year had always had its present length of about sixty-five terrestrial years, the second insisting that the seasonal period must have been more or less steadily decreasing in length. This group had no suggestions for explaining such a phenomenon but stuck to their interpretation of the data. Dar Lang Ahn was fascinated; it was the first time that he had realized that positive knowledge did not always result at once from scientific investigation.

It remained for the leader of the party to sum up the geological situation over the first meal after Dar and Kruger had returned.

“This seems to be the story of this planet, according to present evidence,” he said. “It originated about as long ago as Earth, give or take a billion years, and as far as we can tell in the same manner. It passed through the usual stage of cooling, and eventually water was able to condense. Its primary atmosphere was probably retained a trifle better than Earth’s, since the velocity of escape here is over twenty per cent higher. Life started, probably spontaneously in the usual manner but possibly from adventitious spores, and developed on a path comparable to that of the other planets with which we are familiar — that is, it drastically modified the primary atmosphere until it became more or less like that of Earth.

During this period, which lasted for most of the planet’s existence, the tremendous climatic changes now associated with its sun’s periodic passage close to Alcyone do not seem to have been occurring; at least, no evidence whatever has been found to suggest they were, and a number of very significant facts indicate the contrary. For example, in some of the fossil beds great numbers of shellfish and other creatures of apparently identical species but widely differing size are found, without any layering which would suggest that the smaller ones died earlier. It would seem from such facts that the life of Abyormen, at that time, was normal from our point of view in its reproductive habits — creatures were born, grew old, and died pretty much at random.

“Life evolved to the stage of air-breathing vertebrates under these conditions, the characteristic types produced all being six-limbed. There is no evidence that intelligent beings evolved.

“Then somewhere between five and ten million years ago, the tremendous temperature changes produced by Alcyone began to occur and virtually all the life of the planet was wiped out. Either a few simple forms survived and gave rise to the present species, which get around the climate situation in the way we now know, or more spores arrived, or a totally new generation of life took place.

“We still know very little about these last few million years; it seems the consensus that we should actually drain this lake and conduct major excavations in its bed to find remains of the life of this period. However, we do know that at the moment the general life of the planet exists under a form of alternating generations which enable it to survive in two widely different environments. Are there any additions or corrections to this summary?”

“Just a comment; astronomical help is urgently needed,” came a voice.

“I agree. I have been recording this little speech and will send the tape up to the Alphard as soon as possible.”

The meal ended with no further contributions to science.

“What do you think of it, Dar?” Kruger asked later. “Does this go very badly against what your Teachers have told you?”

“It doesn’t conflict at all; they never told us anything about such possibilities. Knowing what the Teachers are, now, I can suppose that is because they never thought of them themselves.”

“Isn’t there some chance of your Teachers’ objecting to your telling all this? Or, if they don’t object, at least some of the ‘hot’ Teachers will.”

“I’ve been thinking about that. I think our own Teachers will be as interested as I am, and I have come to the conclusion that all the other Teachers know about our doings is what our own report to them by radio. The others couldn’t live anywhere near the Ice Ramparts.”

“Not even underground?”

“A long way down, maybe, but they still couldn’t watch very closely. For one thing, didn’t that one at the geyser village mention that there was no way for you to see him or him to see you, since no barrier that would keep you both safe could be seen through?”

“I hadn’t thought of that. But if he depends on reports from your Teachers, why couldn’t they have just said they had killed me, instead of actually trying to carry out his orders?”

“Well, if that ever occurred to them they probably thought that the reason he wanted you killed was of such a nature that he was bound to detect the results if you weren’t. If my people did learn a lot of your science right afterward, for example, it would be quite hard to hide.”

“I suppose so. Still, I’d certainly take a chance rather than kill a friend.”

“Perhaps they weren’t sure how much of a friend you were. Remember, they hadn’t been with you as long as I, and — well, you do have some rather odd characteristics, you know. I can understand that ‘hot’ Teacher’s feeling that way.”

“I suppose so. We know each other pretty well now, but we still find each other queer at times. It doesn’t bother me any more, though.”

“Nor me.” The two looked at each other with a more nearly complete understanding, in that moment, than they had ever achieved before or were to attain later.