A receptaculitid from the Middle Ordovician Pogonip Group, at Tucki Mountain, Death Valley National Park. From the westernmost exposures of an association of several world-famous geologic rock formations whose correlative age-equivalent outcrops occur in Nevada and western Utah.

Called scientifically genus=species Ischadites mammillaris. An extinct, enigmatic organism of unestablished phylogenetic affinitdy, though not a few paleotologists suggest that it's a variety of green algae. Photograph courtesy Dick LaForge.