A map of North America in Jurassic timesDuring the Jurassic Period, North America lay close to Europe. The Atlantic Ocean, which now separates the two continents, had not yet opened up and there was no land link between North and South America across Central America as there is today. The polar regions—what is now Alaska and Canada—had no ice or snow, even in winter; the climate was far too warm. Forests of conifers such as redwoods and Chile pine (“monkey-puzzle”), along with ginkgos, cycads, tree ferns and horsetails, covered vast areas of North America, providing a great deal of food for the huge Jurassic plant-eating dinosaurs.
Life in the swamps
A swamp in North AmericaWith so much warmth and rain, many parts of Jurassic North America were covered in muddy swamps and marshes. The giant sauropod Diplodocus, along with the shorter but heavier Apatosaurus, stripped leaves from tall trees. Stegosaurus had tall plates of bone on its humped back. Perhaps these soaked up the sun’s heat, so that Stegosaurus could be warmer and more active. It swished its spiky tail to defend its young against the fierce, twin-horned predator Ceratosaurus.
Allosaurus feeds hungrily on its kill of Camarasaurus
The Morrison Formation includes an area of about 1.5 million sq km (600,000 sq miles) of the western United States. Only a tiny part of it has so far been excavated by palaeontologists.
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