United States Ancient trackway

theropod , sauropod tracks under water in paluxy river

in united states, dinosaur footprints , trackways found in glen rose formation, famous of these being paluxy river site in dinosaur valley state park. these first sauropoda footprints scientifically documented, , designated national natural landmark in 1969. large 3 feet across. prints thought have been preserved in tidal flat or lagoon. there tracks 2 types of dinosaur. first type of tracks sauropoda , made animal of 30 50 feet in length, perhaps brachiosaurid such pleurocoelus, , second tracks theropoda, animal of 20 30 feet in length, perhaps acrocanthosaurus. variety of scenarios proposed explain tracks, represent twelve sauropods herd, followed later 3 theropods may or may not have been stalking -- not attacking.