| A mass of broken and complete salterella shells embedded in a coquina association from the Lower Cambrian Harkless Formation, Gold Point fossil site, Esmeralda County, Nevada. Salterella was once believed to represent an early, primitive variety of cephalopod, but in the late 1970s paleontologist Ellis Yochelson concluded that it is a unique type of animal, worthy of its own Phylum, Agmata. |