The Colorado River has been carving its way through northern Arizona for millions of years, but what really stops people in their tracks are the rocks of the Tonto Group in the Grand Canyon walls themselves.
From the rim you can trace ribbons of…
The Colorado River has been carving its way through northern Arizona for millions of years, but what really stops people in their tracks are the rocks of the Tonto Group in the Grand Canyon walls themselves.
From the rim you can trace ribbons of…