Chasmatopora

Chasmatopora is an extinct genus of bryozoans which existed in what is now Mongolia, China, Estonia, Russia, Poland, Argentina, the United States and Canada. It was described by Alcide d'Orbigny in 1849, and the type species is "Chasmatopora tenella", which was originally described as a species of "Retepora" by Eichwald in 1842.