Formed 100,000,000 years ago, tracks of three kinds of dinosaurs are preserved in the limestone below Paluxy River. The types include Acrocanthosaurus, a meat-eater; Camptosaurus, a plant-eater that left three-toed bird-like tracks; and Pleurocoelus, a plant-eater that made huge five-toed prints. For years after their discovery about 1910, the tracks remained a novelty, and when the Paluxy River ran low, farmers caught catfish stranded in them. Excavations by a prominent museum and several universities in 1938 brought the tracks to the attention of the world.