Letter, 1 February 1883
Letter, 1 September 1888
Letter from S. W. Ford to B.J. Harrington regarding obituary of Billings.
Advertising postcard from F. Kaldenberg Co. to B.J. Harrington offering specimens of amber with antedeluvian insects.
Letter, 1 August 1872
Letter, 1 July 1887
Letter, 1 November 1889
Letter, 4 May 1896
Letter from George F. Kurz to B.J. Harrington, written from New York.