The benefit of never downloading your photos is that there are forgotten gems in there when you do get around to it. These shots are from a river trip in the Grand Canyon, in Fall 2011. I volunteered on a bighorn sheep research trip, and while looking for sheep feces I also made a ton of magnetic measurements of rocks and checked out the crust flora. Don't ask, these are just things I do in my spare time.
These are some shots from the vicinity of mile 30 or so, or crusts growing on soils derived from the redwall limestone in Marble Canyon.