I've been trying to find (for some time) a late 1960s or early 1970s British children's fantasy, which mixed illustrations from a Victorian-style naturalist's sketch book into an ecological fable.
The plot is as follows - a pair of badgers leave the last wood, and find their way to the edges of a city. There they meet an old naturalist who introduces them to the new animals that have evolved to fit in with the mess humans have left behind. These include the Great Water Bottle, the ant-like Marbles (and in their hill, the Queenie), the Marble Eater (looking like a cylinder Hoover), the deer replacement Steer, and the twisted pylon-like trees. The badgers meet the last of the old animals, who are protecting plants underground with the intent of restoring the old world. There's a culmination in a fire that drives the new animals into the paths of traffic. As the ashes cool, the old animals bring the plants up from below ground and start to rebuild the lost woods.
I can remember roughly where it was in the Children's Library back home on Jersey, and so I'm pretty sure the author's surname was somewhere between the middle of the As and the start of the Bs... I'm also pretty sure the cover was purple...
I can't be the only person who remembers this book. Even Dave Langford and Brian Ameringen don't know what it's called!