Footprints, the footmarks or imprints left at inconceivably remote periods by the feet of various animals on the wet clay or sand of sea-beaches or similar localities, and which are now found at various levels in the solid strata of the earth. The footprints in the Silurian and other very antique rocks are mostly those produced by the claws of crustaceans. In the Triassic rocks of Connecticut, the footprints of 32 or more species of bipeds, and 12 of quadripeds, have been found.
Entry from Everybody's Cyclopedia, 1912.