A spaceship went awry and traveled to the far future. The few people aboard find themselves looking at a gray, steamy Earth. A landing party explores a relatively cool region (Alaska?) and finds it covered with a silicon- and metal-based ecology with plant and animal equivalents. The POV shifts back and forth between the landing party and an intelligent humanoid machine living with his wife in a cave. She spends most of her time in the cave building their child from parts that he forages from the mechanical forest, though some parts they have to make/grow(?) themselves. The landing party encounters them, at first it's rough and the mechanical man defends his wife, and then they come to some sort of understanding and the landing party leaves. The humans speculate that after a nuclear war, autonomous, self-reproducing mining machines may have mutated. One of the humans says of the Earth, "It isn't ours anymore," as they leave for another stellar system in the repaired spaceship.
This is an English-language short story in an anthology, read probably in the 1960s or 70s, or 80s at the latest.