above: The third section where the river has exposed the oldest basaltic rocks of the earth's crust.
left: A campfire, not really necessary for warmth, but pleasant.
Notice that the campfire is in a metal firepan and the ground underneath is protected by an insulating blanket. The wood for the fires was carried down the river with us on the rafts and the ashes were packed out with our garbage. The next day there was absolutely no evidence that there had been a campfire the night before. The guides, both for ethical and regulatory reasons, were very serious about protecting the environment.