1911 Encyclopædia Britannica/Lesley, J. Peter
LESLEY, J. PETER (1810-1903), American geologist, was born in Philadelphia on the 17th of September 1819. It is recorded by Sir A. Geikie that “He was christened Peter after his father and grandfather, and at first wrote his name ‘Peter Lesley, Jr.,’ but disliking the Christian appellation that had been given to him, he eventually transformed his signature by putting the J. of ‘Junior’ at the beginning.” He was educated for the ministry at the university of Pennsylvania, where he graduated in 1838; but the effects of close study having told upon his health, he served for a time as sub-assistant on the first geological survey of Pennsylvania under Professor H. D. Rogers, and was afterwards engaged in a special examination of the coal regions. On the termination of the survey in 1841 he entered Princeton seminary and renewed his theological studies, at the same time giving his leisure time to assist Professor Rogers in preparing the final report and map of Pennsylvania. He was licensed to preach in 1844; he then paid a visit to Europe and entered on a short course of study at the university of Halle. Returning to America he worked during two years for the American Tract Society, and at the close of 1847 he joined Professor Rogers again in preparing geological maps and sections at Boston. He then accepted the pastorate of the Congregational church at Milton, a suburb of Boston, where he remained until 1851, when, his views having become Unitarian, he abandoned 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 of other coal and iron regions. From 1855 to 1859 he was secretary of the American Iron Association; for twenty-seven years (1858-1885) he was secretary and librarian of the American Philosophical Society; from 1872 to 1878 he was professor of geology and dean of the faculty of science in the university of Pennsylvania, and from 1874-1893 he was in charge of the second geological survey of the state. He then retired to Milton, Mass., where he died on the 1st of June 1903. He published Manual of Coal and its Topography (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.