Ammonites and baculites belong to the Phylum Mollusca and the Class Cephalopoda. Cephalopod is Latin for head-foot. Cephalopods represent the largest, most intellegent and agile group of the Phylum Mollusca. They have a distinct head, large eyes, a funnel, and a circle of arms with a pair of grasping tentacles around the mouth or beak. The foot of the cephalopod has been modified into a funnel, which can be pointed in different directions. Water is taken into the mantle and expelled through the funnel. The cephalopod is then pushed in the opposite direction from which the funnel is pointing. All cephalopods, except for some octopi, have either an external shell in which the animal lives in the last chambeer or an internal shell that is linearly chambered or reduced in size. This specimen is a composite. It is meant to be a study of species which may be found loose or in the mud balls found along the Pierre Seaway. One of the theories on the formation of these mud balls is that they formed when portions of the bank eroded off and fell into the water. As it rolled it picked up shells along the way to its final resting place. This would account for the random angles that the shells are found at within the mud balls when they are broken. Many mud balls have few or no shells within; while others have high concentrations of various sizes. Dimensions: 12-1/2" x 11" x 2-3/4"