Adam Sedgwick (1785-1873), British geologist. Sedgwick worked in Cambridge for most 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. In South Wales his friend Murchison had simultaneously worked out the Silurian system, but some strata overlapped with Sedgwick's Cambrian system. The dispute was resolved in 1879 when Charles Lapworth proposed that the Upper Cambrian and Lower Silurian be renamed the Ordovician. In 1881, Sedgwick taught field geology to Charles Darwin before Darwin went on his round-the-world voyage on H.M.S. Beagle.