Cephalopods are the group of animals to which present day Nautilus, squids and octopuses belong. The individual lived at one end of its shell in a body chamber and extended its body out of the aperture, the open end of the shell. The rest of the shell was divided into septal chambers by septa. The chambers were connected by a siphuncular tube through which the animal could control its buoyancy. Genera and species are differentiated mainly by size, shape, siphuncular position and internal structure.
Armenoceras had a long straight shell of medium size with a central siphuncular tube bordered by prominent calcareous deposits.
Cyclendoceras had a large straight shell with a relatively wide offset siphuncular tube bordered by curved septal ends.
Cyrtogomphoceras had a stubby shell with pronounced curvature. The body chamber showed a constricted aperture and the offset siphuncular tube was bordered by incurved ends of the septa.
Diestoceras had a stubby straight shell with a constricted aperture and the offset siphuncular tube was bordered by incurved ends of the septa.
Lambeoceras had a very large straight shell and the central siphuncular tube was relatively narrow and bordered by curved and slightly thickened septal ends.
Narthecoceras is thought to be a calcified rod that perhaps stiffened the body of a shell-less cephalopod in the way that cuttlefish bone does for the modern cuttlefish.
Orthoceras had a long slim straight shell with a central siphuncular tube.
Wilsonoceras had a medium sized shell with pronounced curvature.
Winnipegoceras had a slightly curved shell with a constricted aperture.
These are Snails and their shells grew in a spiral form.
Maclurina grew very large and its shell was a flat spiral.
Hormotoma was medium sized with a high spiral shell which cut vertically shows an overall triangular outline containing smoothly curved elliptical to circular cross-sections.
Loxonema was a snail with a high sharply pointed spiral shell which cut vertically shows an overall triangular outline containing elliptical to circular cross-sections.
These are shellfish with two shells. Though they resemble modern pelecypods (clams) their internal structure is very different. Modern brachiopods are not common.
Megamyonia had a straight hinge line and a thick shell.
Rafinesquina had a large, gently curved and relatively thin shell.
Crinoids are marine animals commonly called Sea Lilies because they have a long stalk like a flower stem with arms at the top like flower petals. The arms are jointed with small protruding finger-like processes that are used to catch food as they wave around in the current.