1008 Clinton St
Philadelphia, PA, USA

J. Peter Lesley House

The J. Peter Lesley House is a historic row house at 1008 Clinton Street in the Washington Square neighborhood of Philadelphia, Pennsylvania, USA. A National Historic Landmark, it was for 27 years the home of John Peter Lesley (1819-1903), one of the leading geologists of the second half of the 19th century. The house is a private residence, and is not open to the public.

Description and history
The J. Peter Lesley House is located in Philadelphia's Washington Square West neighborhood, on the south side of Clinton Street between South 10th and 11th Streets. It is a 3+1⁄2-story brick building, with a gabled roof pierced in front by a gabled dormer, and flanked on the side walls by chimneys. It is three bays wide, with the entrance in the rightmost bay, topped by a Federal style half-round transom window. The interior of the house largely retains features of the later 19th century, despite conversion to multiunit residences and back to single-family use.

J. Peter Lesley rented this building from 1869 to 1897, using it as his home and office. Lesley served for many years as the State Geologist of Pennsylvania, and was a leading authority on geology related to coal and iron ore, especially in Pennsylvania and surrounding states. His pioneering work A Manual of Coal, published in 1856, demonstrated the relationship between topography and geological structure. He supervised the publication of more than 120 state reports produced by its Geological Survey department, which he also directed for many years.

The Lesleys made this address their year-round home until 1885, when Mrs. Lesley was given a house in Milton, Massachusetts. He continued to spend most of his days here until ill health compelled his retirement in 1896, after which he also moved permanently to Massachusetts.

National Register of Historic Places - J. Peter Lesley House

Statement of Significance:

From 1869 until 1896, the building located at 1008 Clinton Street was the rented residence and office of J. Peter Lesley (1819-1903), one of America's foremost geologists of that day. It served as the headquarters/office of Mr. Lesley, who was the Geologist for the State of Pennsylvania and Director of the Second Geological Survey of Pennsylvania from 1874 to 1896. It was here that he did considerable scientific writing and drawing related to the survey and reviewed and edited all of the reports, amounting to 120 volumes, produced by his assistants over a 20-year period.

Although he was the house's most notable occupant, Lesley never owned it. After having spent two years in Europe, 1866-1868, recovering from a nervous breakdown brought on by overwork, he returned with his wife Susan to Philadelphia, resuming his professional work in January 1869. It was about this time that they moved into the Clinton Street house.

Before going to Europe Lesley had been extremely busy as a consultant to coal and iron producers in the State and had written two very important books dealing with mineral extraction: A Manual of Coal and its Topography, in 1856, and The Iron Manufacturer's Guide, in 1859. Lesley's Manual of Coal was "in geology, an epoch-making book of the highest importance and novelty; for it was the first to show how clearly and strongly the topography often indicates the geological structure." That book did much to establish his reputation as a geologist of the first rank, even "in view of the whole world," as perceived by one of his assistants. He had already become favorably known personally to the foremost scientific men of America, through his regular attendance at the yearly meetings of the American Association for the Advancement of Science which he had begun attending in 1849. In the fall of 1856, Lesley became Secretary of the American Iron Association at a salary of $1200 per year. He held that position in the strongly managed organization of ironmasters for the promotion of American iron manufacture until 1864. His Iron Manufacturer's Guide, a volume of 800 pages, contained a discussion of each of the iron manufacturing sites in the country and an in depth treatment of the geological occurrence of the ores. Both A Manual of Coal and The Iron Manufacturer's Guide were much used by geologists and entrepreneurs in developing coal and iron operations and helped to establish his national stature as a geologist.

A present-day assessment of Lesley's national stature is ably summarized by Clifford H. Dodge, staff geologist, Pennsylvania Department of Environmental Resources and Topographic and Geologic Survey:
Lesley was one of the most prominent geologists of the nineteenth century. He was a master topographer and principal early worker in the field of geomorphology. He was one of the first to recognize the important role of subaerial erosion and the influence of lithology and structure on topography. He pioneered the use of topographic and structure contouring and strongly advocated the employment of aneroid altimeters (as well as helped design them) in fieldwork. He was a foremost expert on the geology of coal, iron, and petroleum in Pennsylvania and adjacent states.

Lesley's professional reputation in the field of geology had become so well known that he was much in demand as a consultant in this country and in Canada. During the Civil War there was a great increase in the demand for coal and iron, necessitating the production of accurate surveys to determine their most probable locations. Lesley was quick to respond to that need, "and he was hard worked to the extreme, with handsome results to his pocket, but exhaustion of his strength and health."

During 1863 and 1864, Lesley was busily engaged in providing survey services to the greatly expanded Pennsylvania oil industry. Regarding oil production, he was "probably the first professional geologist to be required to investigate its mode of occurrence and was certainly the first to form rational views on the subject." He was a frequent contributor to scientific journals and to government publications, such as his article on "Coal Oil" in the Department of Agriculture's Report of 1862. In that article he presents the fact that "rock-oil had its origin in the decomposition of organisms, and that it was by no means confined to anticlinal summits, nor to the valleys of streams." Indicative of the level of accuracy in Lesley's predictions about the location of oil deposits was his calculation that oil would be found at about 1100 feet below the Allegheny River at Brady's Bend in Pennsylvania and the actual discovery in 1866 of oil at that location at a depth of 1080 feet.

It was Lesley's work as the Director of the Second Geological Survey of Pennsylvania, serving concurrently as the State Geologist, that brought him the greatest national and international recognition. Hence, it is primarily for that reason that he is recognized as being of national importance in the history of science, although at the time he was already known as one of the foremost authorities on oil, iron ore, and coal.