This collection includes correspondence on natural history and evolution, and especially on his collection and study of shells from Japan and the Pacific islands. Principal correspondents include Louis Agassiz, Charles Robert Darwin, Sir William Henry Flower, Alpheus Hyatt, George Newbold Lawrence, George J. Romanes, Alfred R. Wallace, and the Linnean Society of London.

Correspondence of Charles Darwin with his family, Sir William J. Hooker, Sir John W. Lubbock, William Ogle, Daniel Oliver, John Tyndall, and Sir William Ramsay, 1836-1882. (1 reel). Letters to J. Brodie-Innes, W. H. Bates, Lady Dorothy Nevill, and others (1846-1882); also letters to his wife and son and letters and papers about him (1 reel). Letters from Darwin to G. H. K. Thwaites, William B. Tegetmeier, Albany Hancock, Richard Owen, Bernhard Studer, Auguste H. Forel, J. Moulinie, A. Bohrn, Karl Christoph Vogt, François Joseph Pictet de la Rive, and others.

There is correspondence concerning geology, botany, natural history, natural selection, evolution, British science and scientists, and other scientific topics. Most of the letters are written by Lyell, with a very few items by others.