In 1855 Murchison was appointed director-general of the British Geological Survey and director of the Royal School of Mines and the Museum of Practical Geology in Jermyn Street, London, in succession to Sir Henry De la Beche, who had been the first to hold these offices. Official routine now occupied much of his time, but he found opportunity for the Highland researches just alluded to, and also for preparing successive editions of his work "Siluria" (1854, ed. 5, 1872), which was meant to present the main features of the original Silurian System together with a digest of subsequent discoveries, particularly of those that showed the extension of the Silurian classification into other countries.