Eocene Lizard Track Ichnofossil 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.

The prints are the counterparts and thus are raised from the matrix surface. The lizard footprints are of a front foot and a rear foot and are well defined, with even the claws quite distinct. I don't know what the structure is at the upper right corner, but it could be of the animal digging around.