John Fleming, a Scottish naturalist, born at Kirkroads, near Bathgate, Linlithgowshire, in 1785, died in Edinburgh, Nov. 18, 1857. Although possessing an unusual taste for the natural sciences, he entered the ministry, and about 1807 was licensed as a preacher. In 1808, while engaged in a survey of the western isles, he accepted the living of Bressay in Shetland. About the same time appeared his "Economical Mineralogy of the Orkney and Zetland Islands:" and thenceforth for nearly 30 years his attention was pretty equally divided between his clerical duties and his scientific pursuits. In 1810 he exchanged the living of Bressay for that of Flisk. in Fife-shire. His contributions to public journals and to learned societies now became frequent. In 1822, having furnished the article "Ichthyology for the " Encyclopaedia Britannica," and those on "Helminthology and "Insecta for the "Edinburgh Encyclopaedia." besides numerous papers for the "Proceedings" of the Wernerian society and the royal society of Edinburgh, and the "Edinburgh Philosophical Journal." he published his first important work, the "Philosophy of Zoology" (2 vols., Edinburgh). In the second volume he enunciated a system of classification at variance with those of Linneus and Cuvier, and known as the binary or dichotomous system, the leading feature of which consists in arranging animals according to their positive and negative characters.

In his History of British Animals" (Edinburgh, 1828), the first decided attempt was made by a British naturalist to exhibit the palaeontological history of animals, by the side of those belonging to our epoch. The great principle laid down by him, from which he never receded, is that the revolutions which have taken place in the animal kingdom have been produced by the changes which accompanied the successive depositions of the strata. In 1832 he was called to the chair of natural philosophy at King's college, Aberdeen; but in 1843, having identified himself with the Free church, he was obliged to retire from his professorship. Two years later he was elected to the chair of natural science in the New (Free church) college, Edinburgh, with which he remained connected until his death. In addition to the works enumerated, Dr. Fleming published Molluscous Animals, including Shell Fish" (Edinburgh, 1837),The Temperature of the Seasons" (1851),The Lithology of Edinburgh" (1858), and considerably more than 100 papers, principally on zoology, paleontology, and geology.