Fossilized sediment with a small animal's footprints going across.
19" Long x 9"Wide x 3" Tall
Trace Fossil Slab
Unknown Excavation Source
Unknown age
A fossil trackway (ichnite) of a four legged animal; perhaps a mammal, but it is difficult to tell. Trace fossils can be found in a variety of sedimentary rocks, including mudstone, sandstone, and limestone. The trail is preserved when sediment is deposited quickly; preventing the trace fossils from being destroyed by erosion or weathering.
Example measures: 19" Length x 9"Width x 3" Depth; Unknown weight.
An interesting quiz on trace fossil identification from the University Colorado: https://ucmp.berkeley.edu/science/trackways/trackways5.php