Fossils can be broadly divided into body fossils and trace fossils.

Body fossil – The remains of part (or all) of an actual organism.  In the kits, the trilobite (2), brachiopod (3), dinosaur bone (4), horse tooth (5), petrified wood (6), graptolite (7), fish (8), smooth and jagged-margined leaves (9 and 10), fern (11), shark tooth (12), cave bear tooth (15), and Spinosaurus tooth (16) are all body fossils. 

Synapsid trackTrace fossil – Trace fossils are traces or marks left behind by an organism. They show an organism was there, but are not the actual organism itself (which would be a body fossil). Dinosaur footprints and worm burrows are examples of trace fossils, as are coprolites (fossilized dung or feces). In the kits, the coprolite (1), theropod track (17), and synapsid track (18) are trace fossils.