Desert dirt is very cool! Peggy Wenrick instructed the Wednesday Nature Walk on cryptogamic soil. (Crypto = hidden, gamic = usually: reproduces sexually, from the Greek for 'marriage') She even had a handout! You'll have to settle for a link. Basically, these crusts are living soil, composed of cyanobacteria (aka blue-green algae), other algae, cyanolichen, and mosses. Each species helps bind the soil. This takes a LONG time. Potentially more than one hundred years to form soil like in these photos. Take home message: STAY ON THE TRAIL!
Both photos by Peggy Wenrick
Click on the photos for larger views. Note the fruiting bodies (mushroom-like, filled with spores) in the lower photo. Once you know what you are looking for, you can find this soil all over in the canyon. Thanks, Peggy! You are as cool as dirt :-)