"Once there were brook trouts in the streams in the mountains. You could see them standing in the amber current where the white edges of their fins wimpled softly in the flow. They smelled of moss in your hand. Polished and muscular and torsional. On their backs were vermiculate patterns that were maps of the world in its becoming. Maps and mazes. Of a thing which could not be put back. Not be made right again. In the deep glens where they lived all things were older than man and they hummed of mystery."
The final paragraph, talks about how the stream and the mountains, used to be their, and no longer exist. How all of these natural wonders had existed before man, came, and they exploited carelessly the planet, to the point it caused an uncertain catastrophie. And how this damage is irreversible, at least for a couple thousand years. The story of The Road, in the end, apart of the love between the father and son, is really about the fear of the fall of man. McCarthy may be probably trying to warn us, since the worst can still be averted.