Papers consist of correspondence (1940s to 1970s); photographs of echo sounding seismic operations (1950s-1960s); MIT 1965 summer session materials; cruise journals (1960s), data and reports; his drafts, daily logs, notebooks, proposals, and patent information; trip reports as deputy assistant oceanographer (1970s); lectures and committee minutes; and audograph-soundwriter recordings (1949-1950) of scientific observations at sea, including sound transmissions, reverberation studies, fish noises, and oral discussions and reports. The materials reflect his work and contributions as a geophysicist at the Institution. They also document his involvement and collaboration with other scientists and with the US Navy, his tenure as the first department chairman of Geology & Geophysics and some of his activities as deputy assistant oceanographer at the Office of Naval Research in Washington, DC. Hersey's research included solid earth geophysics, underwater acoustics, physical oceanography, sound scattering by marine animals and marine geology. His papers also detail his involvement in numerous projects while at WHOI, including the Thresher search, AMSOC (American Miscellaneous Society) committee, Project Mohole, the Mantle Project, and the International Indian Ocean Program.