Twelvetrees and W. F. Petterd did petrographic investigations in Cygnet, around 1899. Other unpaid people studied Tasmanian geology such as Paweł Edmund Strzelecki, Joseph Milligan who was a surgeon, R.M. Johnson, Charles Darwin, John Lhotsky and Joseph Jukes. Joseph Milligan sent specimens of a manganese mineral from Frenchman's Cap and Galena to the 1851 Great Exhibition in London. Small amounts of gold were discovered at Fingal and Lefroy in 1851. William B. Clarke, a geologist and Anglican parson, predicted that gold would be found in Tasmania at 146 degrees east longitude line. On 17 July 1859 Charles Gould, a geologist recruited from England, was appointed as the Geological Surveyor of Tasmania by the Tasmanian governor. He began the search for worthwhile minerals in the west, gave up and studied the geology of the eastern half of the state instead. He was commissioned by the Tasmanian Government in 1862 to return to the west coast, he named mountains in the West Coast Range: Mount Lyell after Charles Lyell, Mount Darwin, Mount Huxley and opponents of Charles Darwin were commemorated with Mount Owen, Mount Sedgwick, and Mount Jukes. Gould returned several times but did not find worthwhile mineral deposits. James "Philosopher" Smith discovered the Mount Bischoff tin deposit, for many years the world's richest and largest, on 4 December 1871. This discovery inspired George Renison Bell to find more tin and other minerals in western Tasmania. Dally shortly thereafter found important gold reefs at Beaconsfield and at Lefroy in the northeast. In 1882, Gustav Thureau was appointed Inspector of Mines, later called Inspector and Mining Geologist. In 1889, the position became Geological Surveyor. William Harper Twelvetrees took up the position. He established the Geological Survey library, and mineral and rock collection at the Queen Victoria Museum in Launceston. In 1883, the Mines Office was created from the Commissioners and registrars for mines and goldfields that worked in the Mines Branch of the Lands and Works Department. Bernard Shaw was appointed the Secretary for Mines. The Mines Office gained a Minister for Mines in 1894 and changed its name to Mines Department. Bernard Shaw later became the Police Commissioner. The Mines Department lost its separate existence in July 1989 when it was merged to the Department of Resources and Energy, which has since changed its name several times.