A chartreuse crustose lichen growing on a rock at Inks Lake. Maybe Acarospora contigua? http://www.sharnoffphotos.com/lichens/acarospora_contigua.html Or tuckerae? http://www.sharnoffphotos.com/lichens/acarospora_tuckerae.html UPDATED: I'm leaning toward contigua: https://www.inaturalist.org/observations/5943328