MACLURE, William (1763-1840), the pioneer of American geology, was born at Ayr in Scotland in 1763. After a brief visit to New York he began active life as a partner in the firm of Miller, Hart, & Co., London. Four years later (1796) business affairs brought him again to America, which he thereafter made his home. In 1803 he visited France as one of the commissioners appointed to settle the claims of American citizens on the French Government for spoliations committed during the Revolution; and during* the few years then spent in Europe he applied himself with enthusiasm to the study of geology. On his return home he commenced the self-imposed task of making a geological survey of the United States. Almost every State in the Union from the St Lawrence to the Gulf of Mexico was traversed and mapped by him, the Alleghany mountains being crossed and recrossed some fifty times. The results of his unaided labours were submitted in a memoir to the American Philosophical Society (1809), and published in the Society’s Transactions (vol. vL), together with a geological map, which thus antedates William Smith's great geological map of England by six years. Subsequent survey has corroborated the general accuracy of Maclure’s observations, so far at least as the Primary and Secondary formations are concerned. From 1817 to his death Maclure was president of the Academy of Natural Sciences of Philadelphia, and much of the prosperity of the institution was due to his devoted services. In 1819 he visited Spain, and attempted to establish an agricultural college near the city of Alicante; but with the overthrow of the short-lived Liberal constitution his plans became hopelessly deranged. Returning to America in 1824, he settled for some years at New Harmony, Indiana, endeavouring, ...