Model of the cephalopod, Goniatites.
Image: Jon Augier
Source: Museum Victoria
Fossil of the cephalopod, Goniatites crenistria.
Image: Jon Augier
Source: Museum Victoria
Goniatites was an ammonite; a cephalopod with a distinctive round, coiled shell. Goniatites and related ammonites were abundant in the oceans of the Carboniferous, but were relatively small. The distinctive zig-zag markings on the fossil indicate the internal chambers of the shell.