Chippewaella

Chippewaella patellitheca is a stem-gastropod mollusc from Furongian-aged strata of Late Cambrian Wisconsin. According to Peter J. Wagner, it is the most basal gastropod.
Morphology.
"C. patellitheca" is known from broad, low, cap-shaped or mound-shaped shells around 2 centimeters in diameter. The shell has a slight apex that points posteriorly, and is at the posterior end of a central dorsal ridge.