Via Nicholas, whom I found because I have nothing better to do this morning than check my site referrals and drink coffee, we have here Durango Bill’s Ancestral Rivers of the World. Fans of the geological writing of John McPhee
There are many rivers that flow through mountains rather than around them, indication that the rivers existed before the mountains did. Durango Bill has compiled examples from around the world of such rivers, with maps and an explanation of the two main means by which rivers carve canyons through mountain ranges. He includes one of my favorite such, the Green River flowing through Split Mountain, Utah, on its own page. The mouth of that canyon is pictured below, dog provided for scale:
A related phenomenon: the entrenched meander. The canonical example of same is probably the San Juan Goosenecks. Read Bill’s pages and their formation will be explained, though he doesn’t mention them that I see.
He’s missed a spectacular ancestral river in my region, though. The Manawatu River, in New Zealand’s North Island, rises on the eastern side of the Ruahine and Tararua ranges and separates them as it flows to the west coast of the island (picking up the Pohangina River as it exits the gorge). Perhaps he missed it because what remains of the original mountain chain has been named differently on either side of the gorge? Or, perhaps it’s just that we’re small and tucked away largely off the world stage. Still, being overlooked does have advantages…
Not that the Fox River in Illinois competes for drama, but am reminded of a great headline from Chicago Wilderness Magazine:
BORN AGAIN RIVER:
REMEANDERING THE NIPPERSINK
And McPhee’s books on geology indeed are wonderful. I’ve reread all at least once (Assembling California still stuns), and always walk away with better eyes.