J. Peter Lesley was a geologist and founding member of the National Academy of Sciences who spent most of his career studying the geographic contours and natural resources of Pennsylvania, his native state.
Lesley graduated from the University of Pennsylvania in 1838 and earned his masters degree from the university three years later. As a young man, he joined the first Geological Survey of Pennsylvania, which assigned him to three years on horseback exploring the countryside, drawing maps, and speaking with people in the communities that he encountered.
In 1852, Lesley accepted a job as draftsman with the Pennsylvania Railroad. He later worked as a geologist and lecturer in Europe from 1866 to 1868 before returning to the United States and accepting a position as editor of the U.S. Railroad and Mining Register, as well as a professorship of geology and mining at the University of Pennsylvania. Around this same time, Lesley assumed leadership of the second Geological Survey of Pennsylvania, a project that occupied him for more than twenty years at the end of his career.
Lesley received many international honors for his research and he was a member of multiple honor societies, including the American Association for the Advancement of Science, the American Philosophical Society of Philadelphia, the Academy of Natural Sciences of Philadelphia, and others.