Wikipedia
Gangshanoceras
Gangshanoceras is a fossil nautiloid cephalopod genus included in the orthocerid family Proteoceratidae. It has been found in Ordovician rocks dated from about 478.5 to 468 Ma in China, and from rocks dated slightly younger, about 468 to 461 Ma in Argentina. Six species are known. The type is Gangshanoceras jurongense.