He let out a jet of wet flatulence in his long johns, which seemed so hot and itchy now that he could barely stand them. Then he stepped forward. By the time he had hoisted himself and begun to crawl across the tail-whisking, flyblown bridge, which snorted and shifted beneath him but still held firm and steady, any thought of Scoresby and company, or the Army that he represented and which was in theory bound to support him, was as far away as his horse. He did not want to look in the direction of the man awaiting him in the stretch of raw meadow beyond. His focus was to hold his sphincter clapped shut and to hope the falcon claws that remained fixed to his shoulder did not strengthen their grip.

Then, in midstream, he had what he felt was the strangest series of imaginings yet. If he had seen phantoms and phantasms before, and been confused by their palpability, he now had an idea that the beasts beneath him were not there at all. They were not simply bigger and more numerous variations on the falcon; they were something else. He was wiggling on his hands and knees across thinner air than he could breathe.

The resistance of the beasts’ backs altered as this idea formed. He felt himself squishing and sliding. He had to keep going.

At the slightest hint of doubt, the bridge of skins began to fade beneath him and he felt as if he were falling at first-and then rising-for instead of a bridge of bison across the creek he saw blood-damp acres of their rotting carcasses. Miles of buzzard-picked skeletons. Miles and piles. And, between the heaps of maggot-writhing tissue and sun-brittle bones, white people in alien costumes wandering oblivious, as if in a ritual.