They can represent plants or animals.
Burrows are a type of trace fossil found commonly in sedimentary rocks.
They represent the activity of an organism within the sediment, after the sediment has been deposited. In some areas, burrowing is so extensive that the sedimentary bedding is pervasively disrupted. The process of disruption of deposition-related sedimentary structures is known as bioturbation . One example is insufficient to demonstrate the diversity of burrows, but it does demonstrate their usual appearance in the rock, and the potential for similarity to the specimens discussed in this evaluation. This type of burrow is probably produced by a lobster, crayfish, or other type of burrowing crustacean, as indicated by similar modern burrows and occasional preservation of the crustacean within the burrow as a body fossil.