Nevertheless she spotted tiny flecks of lichen in hollows on the tops of rocks, in pits that caught some snow and then a lot of sun. They were almost too small to see. Lichen: a symbiotic team of algae and fungus, working together to survive, even in thirty millibars. It was hard to believe what life would endure. So strange.

So strange, in fact, that she suited up and went out to look at them. Up here one had to employ all the old careful habits: secure walker, lock doors; out into the bright glare of low space.

The rocks that harbored the lichen were the kind of flat sunporches on which marmots would have sunbathed, if they could have lived so high. Instead, only little pinheads of yellow green, or battleship gray. Flake lichen, the wrist-pad guide said. Bits of it torn away in storms, blown up here, falling on rocks, sticking like little vegetable limpets. The kind of thing only Hiroko could explain.

Living things. Michel had said that she loved stones and not men because she had been mistreated, her mind damaged. Hippocampus significantly smaller, strong startle reaction, a tendency toward dissociation. And so she had found a man as much like a stone as she could. Michel too had loved that quality in Simon, he told her — such a relief in the Underbill years to have even one such charge, a man you could trust, quiet and solid, that you could heft in your hand and feel the weight of.

But Simon wasn’t the only one in the world like that, j Michel had pointed out. That quality rested in the others as well, intermixed and less pure, but still there. Why could she not love that quality of obdurate endurance in other people, in every living thing? They were only trying to exist, like any rock or planet. There was a mineral stubbornness in all of them.

Wind keened past her helmet and over the shards of lava, humming in her air hose, drowning out the sound of her breath. The sky more black than indigo here, except low on the horizon, where it was a hazy purple violet, topped by a band of clear dark blue … oh who could believe it would ever change, up here on the slope of Ascraeus Mons, why hadn’t they settled up here to remind themselves of what they had come to, of what they had been given by Mars and then so profligately thrown away.

Back to the rover. She continued on up.

She was above silver cirrus clouds, just west of the volcano’s diaphanous summit banner. In the lee of the jet stream. To ascend was to travel into the past, above all lichen and bacteria. Though she had no doubt they were still there, hiding inside the first layers of the rock. Chasmoendolithic life, like the mythic little red people, the microscopic gods who had spoken to John Boone, their own local Hesiod. So people said.

Life everywhere. The world was turning green. But if you couldn’t see the greenness — if it made no difference to the land — surely it was welcome to the task? Living creatures. Michel had said to her, you love stones because of the stony quality that life has! It all comes back to life. Simon, Peter; on this rock I will build my church. Why could she not love that stony quality in every thing?

The rover rolled up the last concentric terraces of lava, working less strenuously now as it curved over the asymptotic flattening of the broad circular rim. Only slightly uphill, and less so every meter; and then onto the rim itself. Then to the inner edge of the rim.

Overlooking the caldera. She got out of the car, her thoughts flicking about like skuas.

Ascraeus’s nested caldera complex consisted of eight overlapping craters, the newer ones collapsing down across the circumferences of the older ones. The largest and youngest caldera lay out near the center of the complex, and the older higher-floored calderas embayed its circumference like the petals of a flower design. Each caldera floor was at a slightly different elevation, and marked by a pattern of circular fractures. Walking along the rim changed perspective so that distances shifted, and the floors’ heights seemed to change, as if they were floating in a dream. Taken all in all, a beautiful thing to witness. And eighty kilometers across.

Like a lesson in volcano throat mechanics. Eruptions down on the outer flanks of the volcano had emptied the magma from the active throat of the caldera, and so the caldera floor had slumped; thus all the circular shapes, as the active throat moved around over the eons. Arcing cliffs: few places on Mars exhibited such vertical slopes, they were almost true verticals. Basalt ring worlds. It should have been a climbers’ mecca, but as far as she knew it was not. Someday they would come.

The complexity of Ascraeus was so unlike the single great hole of Pavonis. Why had Pavonis’s caldera collapsed in the same circumference every time? Could its last drop have erased and leveled all the other rings? Had its magma chamber been smaller, or vented to the sides less? Had Ascraeus’s throat wandered more? She picked up loose rocks on the rim’s edge, stared at them. Lava bombs, late meteor ejecta, ventifacts in the ceaseless winds… These were all questions that could still be studied. Nothing they did would ever disturb the vulcanology up here, not enough to impede the study. Indeed the Journal ofAreological Studies published many articles on these topics, as she had seen and still occasionally saw. It was as Michel had said to her; the high places would look like this forever. Climbing the great slopes would be like travel into the prehuman past, into pure areology, into the areophany itself perhaps, with Hi-roko or not. With the lichen or not. People had talked of securing a dome or a tent over these calderas, to keep them completely sterile; but that would only make them zoos, wilderness parks, garden spaces with their walls and their roofs. Empty greenhouses. No. She straightened up, looked out over the vast round landscape, held up and offering itself to space. To the chasmoendolithic life that might be struggling up here, she waved a hand. Live, thing. She said the word and it sounded odd: “Live.”

Mars forever, stony in the sunlight. But then she glimpsed the white bear in the corner of her eye, slipping behind a jagged rim boulder. She jumped; nothing there. She returned to the rover, feeling that she needed its protection. She climbed inside; but then all afternoon on the screen of the rover’s AI, the vague spectacled eyes seemed to be looking out at her, about to call any second. A kind bear of a man, though he would eat her if he could catch her. If he could catch her — but then none of them could catch her, she could hide in these high rock fastnesses forever — free she was and free she would be, to be or not to be if she chose that, for as long as this rock held. But there again, right at the lock door, that white flash in the corner of her eye. Ah so hard.

An ice-choked sea now covered much of the north. Vastitas Borealis had lain a kilometer or two below the datum, in some places three; now with sea level stabilizing at the minus-one contour, most of it was underwater. If an ocean of similar shape had existed on Earth, it would have been a bigger Arctic Ocean, covering most of Russia, Canada, Alaska, Greenland, and Scandinavia, and then making two deeper incursions farther south, narrow seas that extended all the way to the equator; on Earth these would have made for a narrow North Atlantic, and a North Pacific occupied in its center by a big squarish island.

This Oceanus Borealis was dotted by several large icy islands, and a long low peninsula that broke its circumnavigation of the globe, connecting the mainland north ofSyrtis with the tail of a polar island. The north pole was actually on the ice ofOlympia Gulf, some kilometers offshore from this polar island.