Between 1764 and 1781, the Scots surveyor George Gauld was assigned by the British Admirality to chart the waters of the Gulf Coast off British West Florida, an area that extended from New Orleans to the modern-day Florida. In 1773, Gauld submitted some of his findings to the APS, probably in hopes of having them published in the Transactions, and although these were not published, they became one of the first mansucripts entered into the Society's collections. Contains occasional brief references to Native peoples of the areas described. The Gauld manuscript also includes an extract of a letter from John Lorimer to Gauld, 1772, and a sketch of the Middle and Yellow Rivers of West Florida by Thomas Hutchins. When it was received at the APS, it was endorsed: "This long uninteresting Paper can hardly obtain a Place in the Transactions of a Philosophical Society. It should however be preserved in the Files for the Use of Historians or map makers."

These are primarily papers relating to the work of the United States Army Corps of Topographical Engineers, with special reference to surveys of harbors of the eastern United States. Some papers and letters relate to natural history and are addressed to John Lawrence LeConte. Correspondents include Rutherford B. Hayes, Joseph Henry, Daniel Parker, and E.G. Squier.

This collection contains mostly entomological material, with much information on the description and identification of particular insects, entomological collections, and the study of entomology in Europe and the United States. In addition, there are materials on medicine and hospitals during the American Civil War, on the Corps of Topographical Engineers, the United States Army, on natural history in the United States, and on the LeConte's family. Some letters are written to President Rutherford B. Hayes and concern the Commissionership of Agriculture, for which LeConte was considered, but not appointed. Letters of John Eatton LeConte and Joseph LeConte are included.

Through his craniometic studies of human races, the Philadelphia physician Samuel George Morton (1799-1851) exerted a profound influence on the development of physical anthropology in antebellum America, and made substantial contributions to mineralogy, paleontology, and natural history. Relating primarily to Morton's scientific interests, the Morton Papers include insights into Morton's perspectives on education, medical practice, geology and mineralogy, craniology, paleontology, the Wilkes Exploring Expedition (also known as the United States Exploring Expedition 1838-1842), and his two major monographs, the Crania Americana and Crania Aegyptiaca. Several of the letters were written by Morton in his capacity as corresponding secretary of the Academy of Natural Sciences of Philadelphia. Also included in this collection are Morton's "Some Remarks on the Infrequency of Mixed Offspring Between the European and Australian Races" (1850), Joseph Barclay Pentland's notes on the aborigines of Peru (ca. 1840?), and newspaper clippings on Morton's death; a diary of Morton's trip to the West Indies, 1834, a set of craniological sketches for use in Crania Americana, and a microfilm of letters in private hands, written to Morton, 1838-1844

George Ord made important contributions as an ornithologist and writer but is also famous for his contempt of fellow ornithologist John James Audubon. Throughout his life he published numerous scientific articles and assisted in completing Alexander Wilson's life's work, American Ornithology; or, The Natural History of the Birds of the United States. Ord also left his mark as a member of the American Philosophical Society and as the president of the Academy of Natural Science of Philadelphia. The George Ord collection consists primarily of outgoing personal correspondence to Charles Waterton ranging from 1831 to 1866 that highlights Ord's professional as well as personal affairs, most notably his hostility toward Audubon. The collection is supplemented by correspondence of Ord's to and from various individuals regarding personal and business matters.