Receptaculitid fragments from the Middle Ordovician Pogonip Group, Grapevine Mountains, 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.

Image ©2022 University of California Museum of Paleontology; photographed by Bob Day. I edited the image with photoshop. Used here under the parameters of the Creative Commons Attribution 3.0 (CC BY 3.0) license.