Buro Mesa Pouroff. 1 mile, round-trip. A fairly level path, across the sand, through the cacti, to a break in another one of Big Bend’s giant rock walls. Step down into the river bed and follow it back, the towering walls narrowing till they meet. We hear there can be water, but it’s bone dry. It’s left it’s mark over the years, a giant chute formed where the rock walls meet.