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Adam Sedgwick (1785-1873), British geologist, aged 47. After graduating in mathematics in 1808, he remained at Cambridge for the rest of his life, being appointed professor of geology in 1818. In 1835 he worked out the stratigraphic succession of fossil-bearing rocks in North Wales, naming the oldest of them the Cambrian period (now dated at 500-570 million years ago). In South Wales his friend Murchison had simultaneously worked out the Silurian system, some strata of which overlapped with Sedwick's Cambrian system. The celebrated dispute which followed was only resolved in 1879 when C. Lapworth proposed that the Upper Cambrian and Lower Silurian be renamed the Ordovician.
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