Thomas Belt (1832-1878), English geologist and naturalist, was born at Newcastle-on-Tyne in 1832, and educated in that city.
As a youth he became actively interested in natural history through the Tyneside Naturalists Field Club. In 1852 he went to Australia and for about eight years worked at the gold-diggings, where he acquired a practical knowledge of ore deposits. In 1860 he proceeded to Nova Scotia to take charge of some gold-mines, and there met with a serious injury, which led to his return to England.
In 1861 he issued a separate work entitled Mineral Veins: an Enquiry into their Origin, founded on a Study of the Auriferous Quartz Veins of Australia. Later on he was engaged for about three years at Dolgelly, another though small gold-mining region, and here he carefully investigated the rocks and fossils of the Lingula Flags, his observations being published in an important and now classic memoir in the Geological Magazine for 1867. In the following year he was appointed to take charge of some mines in Nicaragua, where he passed four active and adventurous years the results being given in his Naturalist in Nicaragua (1874), a work of high merit. In this volume the author expressed his views on the former presence of glaciers in that country. In subsequent papers he dealt boldly and suggestively with the phenomena of the Glacial period in Britain and in various parts of the world. After many further expeditions to Russia, Siberia and Colorado, he died at Denver on the 21st of September 1878.