The Man Who Awoke by Laurence Manning

Then the airship turned about and as it did so Winters caught sight of one gray pile of masonry-a tower tip-showing above the forest. Surely it must have taken thousands of years to accomplish this oblivion of New York! And yet, he thought to himself, even one century makes buildings old.

He scarcely looked out of the window on the way back, but sat engrossed in sad thoughts and mournful memories. They landed once more in the village clearing, and he continued his tour under the Forester's guidance. When the afternoon was over he had gathered a confusing mass of general information about life in the new age. Metals were carefully conserved and when a new colony was started its supply of metal utensils and tools was the final great gift of the parent villages. Fanning was entirely unknown, and grain-which the Forester did not know except as "plant-seed"-was not used for food, although primitive races had once so used it, he said. Everything came from trees now: food, houses, clothing-even the fuel for their airships, which was wood alcohol.