After a brief career in the Congregational church, J. Peter Lesley (1819-1903) left the ministry in 1852 to work full-time as a geologist. Having gained experience in structural geology and stratigraphy with the First Pennsylvania Geological Survey (1836-1842), Lesley became an expert in the geology of coal, working for the Pennsylvania Railroad and other corporations and conducting some of the first systematic studies of the state's hydrocarbon resources. A long-time professor at the University of Pennsylvania, he was elected to the APS in 1856, serving variously as its librarian, secretary, and vice president, and he was selected as Director of the Second Pennsylvania Geological Survey (1875-1889). The Lesley Papers include letters to and from Peter Lesley and his wife, Susan on geology, coal and iron mining, abolition, educational reform, organized charity, and Unitarianism. The collection offers important insight into academic and applied geology in late 19th century Pennsylvania, the development of the coal and iron industries, as well as into the Lesleys' progressive social and intellectual milieu. It is divided into three series: Lesley's general correspondence, his correspondence with his brother Joseph, and microfilms of Lesley's research notes.

A collection of letters, legal papers and financial records of three generations of the prominent Philadelphia family. Spanning 1745-1955, detailed are the legal cases and political advocacy work of John Kintzing Kane (1795-1858), Robert Patterson Kane (1827-1906), and Francis Fisher Kane (1866-1955). Also includes correspondence, architectural drawings, and photograph albums of the Cope family. Robert Patterson Kane's daughter Eliza Middleton Kane (1863-1952) married the Philadelphia architect Walter Cope (1860-1902) in 1893. The APS papers of Elisha Kent Kane are in call no. B K132.