Coprolites

Body fossils are the physical remains of an actual organism (shells, bones, teeth, plant leaves, etc.), while trace fossils (burrows, coprolites, footprints, trackways, etc.) preserve evidence of an organism’s activity or behavior.

The fossilized remains of food found between the ribs of some specimens, in the place where the stomach was, together with fossil excrement, called coprolites, usually attributed to these animals, prove that they fed largely upon fishes, squids, belemnites, and probably other invertebrates.