LESLEY, J. PETER (1819-1903), American geologist, was born in Philadelphia Sept. 17, 1819. He was educated for the ministry at the University of Pennsylvania, where he graduated in 1838. Sub-assistant on the first geological survey of Pennsyl vania under Professor H. D. Rogers, he was afterwards engaged in a special examination of the coal regions. On the termination of the survey in 1841, he renewed his theological studies at Princeton seminary, at the same time giving his leisure to assisting Professor Rogers in preparing the final report and map of Pennsylvania. He was licensed to preach in 1844; paid a visit to Europe, and entered on a short course of study at the University of Halle. Returning to America, he worked two years for the American Tract Society. At the close of 1847 he again joined Professor Rogers in preparing geological maps and sections at Boston. In 1851 he left the ministry and entered into practice as a consulting geologist. In the course of his work he made elaborate surveys of the Cape Breton coal-field, and other coal and iron regions. From 1855 to
1859 he was secretary of the American Iron Association; for 27 years (1858-85) he was secretary and librarian of the American Philosophical Society; from 1872-78 he was professor of geology and dean of the faculty of science in the University of Pennsyl vania, and from 1874-93 he was in charge of the second geologi cal survey of the State. He then retired to Milton, Mass., where he died June 1, 1903. He published Manual of Coal and its Topog raphy (1856); The Iron Manufacturer's Guide to the Furnaces, Forges and Rolling Mills of the United States (1859).
See memoir by Sir A. Geikie in Quart. Journ. Geol. Soc. (May 1904) ; and memoir (with portrait) by B. S. Lyman, printed in advance with portrait, and afterwards in abstract only in Trans. Amer. Inst. Mining Engineers, xxxiv. (1904), p. 726.