The Cold Lairs

Starfarers, 20.

Exploring a planet in a ship's boat:

no danger of infection because, although the life is protein in water solution, it is too different;

few large animals;

only relics of intelligent beings (see below);

ground cover of yellow fronded blades, a few centimeters tall;

darker membranous foliage on trees (?);

small gauzy-winged flyers;

ivylike plants reclaiming bright walls and iridescent towers;

Kilbirnie says, "'The Cold Lairs.'" (p. 166)

She says that the phrase comes from an old book. I thought that it sounded like Tolkien but it is Kipling.

This time, having posted about it, I am more likely to remember it.

Why has a civilization ended? Why has an intelligent species gone into the cold?