Correspondence, manuscripts, notes, and photographs of Kay, including files of correspondence from his student years to the time of his death, primarily on professional and academic matters; geological field notebooks, 1923-1975; manuscript materials for his book, STRATIGRAPHY AND LIFE HISTORY (written with E.H. Colbert); files on the Gander Conference, 1964-1970; manuscripts and typescripts of various lectures and articles; syllabi and various other academic files; and photographs and illustrations, primarily those used in STRATIGRAPHY AND LIFE HISTORY.