Amphibian Leg Bone Fossil
A boy from LaMoille found this fossil in a quarry near LaSalle.
The fossil is a Pennsylvanian amphibian leg bone, which appears to be preserved with chert. The matrix rock is a limey mud (kind of odd for a freshwater animal). Speculation: the poor critter may have been washed into the wrong environment and died as a result.
Close examination shows some very nice striatons along the bone.
Four pictures from slightly different angles.