Family correspondence; correspondence with Gwen Raverat (ne Darwin), 1903-50; and general correspondence, alphabetically arranged.
 Early genetics research: notebooks, sketches and publications; unpublished notes, essays, lectures, and sketches; and publications notes, drafts, and proofs, 1920-70.
 Relations with the Bateson family.
 Photographs of Nora Barlow, homes and family; Farrers and Erskines, 1840s-; Darwins and Batesons, 1880s-; and miscellaneous, cousins, and friends.
 Publications: journal articles and cuttings, and books annotated with Nora Barlow's notes (mostly on Darwin and related subjects).
 Diaries; sketch books and travel notes; and acquisitions of Darwin material by Cambridge University Library.