Here’s a nicely preserved fossil sand dollar from California. It has been prepared by air abrasion to better show the plate boundaries.
This is Dendraster gibbsii, first described by Auguste Rémond in the 1860s. This species is relatively common in the Siphonalia zone of the Etchegoin Formation (Lower Pliocene). It comes from the Kettleman Hills (west-central Kings County) of south-central California, USA.
Classification: Animalia, Echinodermata, Echinozoa, Echinoidea, Clypeasteroida, Scutellina, Dendrasteridae
Dendraster gibbsii (4.3 cm across) from the Etchegoin Formation (Lower Pliocene) of the Kettleman Hills, California, USA.