What is "chicagooceras"

Chicagooceras is an orthocerid genus from the Silurian of North America.

Shells are short, breviconic, and faintly curved. Sutures are fairly wide spaced and though straight, slope slightly, dorso-ventrally, to the rear. Siphuncle: small, slightly ventral of the center, thought to be orthochoanitic (straight septal necks) and cylindrical (tubular connecting rings).