There are letters to and from Thaddeus W. Harris, Frederick E. Melsheimer, Levi W. Leonard, Henry McMurtrie, and Margaretta Hall Morris, on topics in natural history.

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.