I was on another cliff looking down at the dwellings. The black on the rock is called desert varnish. It occurs as rain runoff deposits and modifies minerals on the top layer of sandstone. You'll find native American petroglyphs pecked into rock faces, exposing the lighter sandstone underneath.
Wow, I'd love to see this in person. Amazing how they created such beautiful buildings in the walls of the cliffs and overhangs. There is one outside of Colorado Springs CO but it's not that big. Thanks for giving us this fabulous shot