What is "chancelloria"

Chancelloria is a genus of early animals known from the Middle Cambrian Burgess Shale, the Comley limestone, the Wheeler Shale, the Bright Angel Shale and elsewhere. It was first described in 1920 by Charles Doolittle Walcott, who regarded them as one of the most primitive groups of sponges. This appears unlikely, and it is currently placed in the enigmatic group Coeloscleritophora.