NEW THINKING. “Although quantitative studies have yet to be undertaken in the Precambrian, it is clear that the rock record from the critical interval around the Precambrian‐Cambrian boundary is less complete than we might like. In many localities around the world, shallow‐marine Cambrian or Ordovician rocks lie unconformably above Precambrian rocks. This “Great Unconformity” records a prolonged period of continental denudation in the latest Neoproterozoic followed by a major marine transgression, suggesting that many latest Ediacaran shallow‐marine rock sequences – reflecting environments that may be expected to contain the highest diversity of animal life – have been eroded away.”
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