Other Types of Fossils
Snails and insects made little tracks in the mud when they moved across the surface. Some of these tracks were preserved and look like wavy lines, as seen on the rock slab above.
Many animals dig into soft mud or lake bottoms to escape predators or find food. It is very hard to figure out what type of animal created a fossilized burrow, but clams, snails, and many other small creatures could make burrows.