Lizard and Bird Trackway Association from Green River Formation

This fossil trackways plates was collected decades ago from a site has been recently rediscovered. Most probably, the area was a near-shore shelf along Uinta Lake that existed during the Eocene.

There are three lizard tracks and three bird tracks on this plate. Bird tracks are somewhat common at some localities in Utah, but this is the first occurence I have seen of bird tracks being in association with lizard tracks. The smaller bird track Ichnogenera are normally considered to have been made by Eocene Avia resembling modern sandpipers or plovers.

The prints are the counterparts and thus are raised from the matrix surface. The lizard tracks are of the front and hind foot. Note in the close up pictures that the lizard claws are most distinct. There is a bird track between the lizard tracks. This is an unusual association.