The Puluxy River, which winds through Dinosaur Valley State Park, is a tributary of the Brazos River. There was an ancient sea here at one time. The river carved a path through the ancient rock formations aeons ago. The dinosaur tracks were left on the soft mud edging the water, sediment filled the imprints and hardened, leaving the evidence of their presence we see today.
A path leads down to the river, but you have to climb over large boulders and fallen tree limbs. Once you are down to river level, you'll need to be careful as you progress along the edge. The river's depth varies depending on rainfall that feeds it.
The Paluxy River has several spots in it where you can see the dinosaur tracks in the solid rock. This is where the first Sauropod tracks in the world were discovered. The Sauropod was a plant-eating reptile more that 60ft long. There are also tracks of a Theropod which was a 12ft tall meat eater.