Footprints in the Mud

Footprints in the Mud. . This rock face cuts through the shallow north bank of the waterhole. The contorted sediment layers were produced by the feet of mammals walking through the waterhole. The thin white mud layer records several such footprints or tracks. The viscous mud formed a mold for each footprint and later volcanic ash and sand washed into the waterhole, filling and preserving the footprints. , Captions , Lower Left: , 4. Fossil soil covering waterhole , 3. Sand and ash that filled waterhole , 2. Mammal tracks in ashy lime mud , 1. Floor of the waterhole, Upper Right: Called Dinohyus, meaning "terrible pig," this entelodont was not related to modern pigs. In 1986 paleontologists found the marks of their teeth on chalicothere limb bones at Carnegie Hill., Lower Right: Entelodonts scavenge the carcasses of rhinoceroses and chalicotheres in and near the waterhole. Their hooves left identifiable footprints in the soft waterhole muds.