Amphiscapha

Amphiscapha is a fossil gastropod mollusk, or less likely a monoplacophoran, genus from the Pennsylvanian and Lower Permian of North and South America, included in the family Euomphalidae. It is sometimes regarded as a subgenus of Straparollus, S. (Amphiscapha) Knight 1942

Description
The shell in this genus is hyper strophic discoidal, with a flat base and a concave upper side. The location of what is presumed to be the exhalent channel is marked by a smooth or rugose ridge along the upper-outer margin, which lies along the edge of a flat to concave outer rim.