A decade ago, hiking the crest of the Manzano Mountains, I picked up an odd fossil (left):
I ran it around to all the paleontologists I knew. A worm tunnel? A beetle track? Trunk of a very small elephant? (Right.)
But not the right paleontologists, apparently, for no one could say. Heavy and red with iron, the mystery piece has roamed around my desk for years, petted and puzzled over.
Then, in the museum at Joggins Cliffs in Nova Scotia, I found Artisia (right). It’s a cast of the pith of Cordaites, a treelike plant that grew huge in what is now the Bay of Fundy–and, it seems, in what would become the Manzanos Crest Trail. I checked: Carboniferous-Permian boundary. Both places.
300 million years later, I can crow, “That’s it!”
WORLD-BUILDING and WILDERNESS: 
I looked up Cordaites, and found that it still has one living relative, the ginkgo tree. The ginkgo is infamous for its stinky fruit, resembling some of the more odiferous cheeses. If Cordaites was anything like it the Carboniferous forests must have been Odiferous.