In 1909 a fossil bed was found in Canadian rocks high up in the Rocky Mountains. Examination of the tiny fossils in this rock revealed very small creatures. The fossils found here are unique and no animals like these have been discovered anywhere else. Special conditions in the shallow seas where these animals lived allowed their delicate structures to be preserved, buried in mud. Many of these animals crept about on the sea-bed, feeding on small organisms in the mud. Some were active predators. Anomalocaris was about 60 cm long and a powerful swimmer. It was armed with grasping claws and a circular mouth lined with cutting blades, enabling it to make short work of its far smaller prey.
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