Lesley, J. Peter, 1819-1903

When J. Peter Lesley (1819-1903) graduated from the University of Pennsylvania in 1838, he intended for the Presbyterian ministry, but when ill health intervened, he was set off on a path that would make him one of the most influential geologists in 19th century Pennsylvania. In order to help rebuild his strength and restore his health, Lesley accepted an appointment with the first Pennsylvania Geological Survey under the direction of Henry Darwin Rogers and engaged in structural and stratigraphic work and topographical and geological mapping in the Pennsylvania anthracite belt. By 1841, he had recovered sufficiently to return to his divinity studies at Princeton Theological Seminary, but continued all the while to work for the Survey on a part time basis, mostly in preparing maps.

After a trip to Europe in 1844 to polish off his ministerial education, Lesley accepted a pulpit in rural central Pennsylvania, and moved three years later to take the helm of a Congregational church in Milton, Massachusetts. There he came into contact with a politically progressive, intellectually stimulating crowd that included Lydia Maria Child, James Freeman Clarke, Thomas Wentworth Higginson, and the fringes of the Transcendentalists and reformers. A young Unitarian member of this circle, Susan Inches Lyman, became Lesley's wife in February, 1849, and both shared their associates' progressive political and social vision.

As he had all along, Lesley continued to work on an occasional basis for the Geological Survey until 1852, when a long-standing conflict with Rogers over credit for field assistants led him to resign. That year marked an even more profound change in Lesley's life, as he also decided to leave the church and return home to Pennsylvania. Coinciding with the period of extraordinary expansion in the coal and rail industries in Pennsylvania, Lesley devoted himself fully to geological work. Employed by the Pennsylvania Railroad Company and other corporations, Lesley was an important cartographer - one of the first to employ contour lines to represent topography - and was an important writer and synthesizer of knowledge about the coal and iron regions. He is credited with some of the first systematic studies of coal, oil, and gas resources in the state.

Lesley's rising prestige in scientific circles led to his election to the American Philosophical Society in 1856, where he instilled himself in the Society's leadership, serving as librarian (1858-1885), secretary (1859-1887), and vice president (1887-1898). During his tenure as librarian, he introduced a new system of arranging books by subject, anticipating in some ways Melvil Dewey's system, but employing small spine labels arranged in the colors of the spectrum to represent the areas of knowledge. He was, as well, a charter member of the National Academy of Sciences in 1863.

Lured to the University of Pennsylvania as Professor of Mining in 1859, Lesley became a fixture there, too. Lesley's acquisition of a major collection of fossils, rocks, and minerals from James Hall, state geologist of New York, helped consolidate geology as a major subject of study at Penn. Lesley later became Professor of Geology and Mining Engineering and Dean of the Science Faculty, and in 1875, he was appointed Dean of the newly formed Towne Scientific School.

The continuing importance of the oil industry to Pennsylvania's economy led to calls for a second state Geological Survey, and for the duration of its existence, from 1874 to 1889, Lesley served as Director. An immense operation by the standards of the first Survey, at least, the second Survey was also immensely productive, issuing dozens of publications on the topography, geology, paleontology, and mineral resources of the state. He was in the midst of preparing a state-mandated final report for the Survey in 1893 when he suffered a complete breakdown. He never recovered.

Lesley died in 1903. One of his two daughters, Mary, married the prominent Minneapolis businessman, Charles W. Ames (1855-1921), and the other, Margaret Lesley Bush-Brown (1857-1944), became a well known artist, some of whose portraits hang in the APS.

From the guide to the J.P. Lesley Papers, 1826-1898, (American Philosophical Society)