Rivers and streams flowing away from rapidly eroding uplands can carry vast quantities of broken rock fragments in the form of grains of sand and silt.(dinosaur equipment) They are spread across the lowlands as the current slackens. The result may be accumulating beds of fertile soil in which plants grow. So, in desert areas, the river supports the riverside vegetation and the seasonal floods spread layers of silt over the landscape, fertilizing it. The River Nile, with its annual floods, keeps the Egyptian desert alive and was responsible for producing one of the earliest prolific farming civilizations.
In Triassic times the vast supcrcontinent of Pangaea was beginning to break up. (dinosaur exhibition equipment)The interior was still arid, being so far from the sea, and life could only really flourish in the flood plains of rivers. It was the time of the prosauropods – the first big plant-eating dinosaurs – the early relatives of the huge long-necked sauropods. They fed on the cycad-like plants that grew close to the ground, and also reached up to browse the coniferous trees that lined the water courses. (dinosaur playground equipment)This heavy browsing led to the evolution of trees and foliage that hnd strong, sharp, sword like leaves as a defence, such as the monkey puzzle tree that still exists in the mountains of South America and in ornamental gardens across Europe. Among the predators, the various crocodile relatives, such as the phytosaurs, were giving way to the first of the theropods. When the plant-eaters were attracted to the water and became trapped in quicksands, their great weight preventing them from escaping, the mcatcaters would take advantage of their helplessness. Remains of all these animals are found in the rocks formed from the river sandstones and the silty flood deposits of the rime.
Occasionally their fossils tell the story of trapped animals devoured by predators, or even of animals killed by the changing seasonal conditions.
Petrified Forest National Park
The most famous fossil occurrence of a Triassic desert waterside habitat is Petrified Forest National Park in Arizona, USA. Close by. at Ghost Ranch, a pack of meat-eating theropods. Coelophysis. was discovered as articulated skeletons. (dinosaur theme park equipment)The evidence shows that they died from dehydration around a drying water hole. The best evidence for prosauropods being caught in quicksand and killed by predators comes from the Frick Brick Quarry. Switzerland. Almost identical circumstances are known from the Molento and Lower Elliot Formations of South Africa, showing how widespread these habitats were on Pangaea.