Actually, Nanao told him, most of the basins were intensively cultivated. “This basin was planted by Abraham.” Each little region was the responsibility of a certain gardener or gardening group.

“Ah!” Sax said. “And fertilized, then?”

Tariki laughed. “In a manner of speaking. The soil itself has been imported, for the most part.”

“I see.”

This explained the diversity of plants. A little bit of cultivation, he knew, had been done around Arena Glacier, where he had first encountered the fellfields. But here they had gone far beyond those early steps. Labs in Sabishii, Tariki told him, were trying their best to manufacture topsoil. A good idea; soil in fellfields appeared naturally at a rate of only a few centimeters a century. But there were reasons for this, and manufacturing soil was proving to be extremely difficult.

Still, “We pick up a few million years at the start,” Nanao said. “Evolve from there.” They hand-planted many of their specimens, it seemed, then for the most part left them to their fate, and watched what developed.

“I see,” Sax said.

He looked more closely yet. The clear dim light: it was true that each great open room displayed a slightly different array of species. “These are gardens, then.”

“Yes . . . or things like that. Depends.”

Some of the gardeners, Nanao said, worked according to the precepts of Muso Soseki, others according to other Japanese Zen masters; others still to Fu Hsi, the legendary inventor of the Chinese system of geomancy called-feng shui; others to Persian gardening gurus, including Omar Khayyam; or to Leopold or Jackson, or other early American ecologists, like the nearly forgotten biologist Oskar Schnelling; and so on.

These were influences only, Tariki added. As they did the work, they developed visions of their own. They followed the inclination of the land, as they saw that some plants prospered, and others died. Coevolution, a kind of epigenetic development.

“Nice,” Sax said, looking around. For the adepts, the walk from Sabishii up onto the massif must have been an aesthetic journey, filled with allusions and subtle variants of tradition that were invisible to him. Hiroko would have called it areoformation, or the areophany. “I’d like to visit your soil labs.”

“Of course.”

They returned to the rover, drove on. Late in the day, under dark threatening clouds, they came to the very top of the massif, which turned out to be a kind of broad undulating moor. Small ravines were filled with pine needles, sheered off by winds so that they looked like the blades of grass on a well-mowed yard. Sax and Tariki and Nanao again got out of the car, walked around. The wind cut through their suits, and the late-afternoon sun broke out from under the dark cloud cover, casting their shadows all the way out to the horizon. Up here on the moors there were many big masses of smooth bare bedrock; looking around, the landscape had the red primal look Sax remembered from the earliest years; but then they would walk to the edge of a small ravine, and suddenly be looking down into green.