Letter concerning the identification of a sample fossil from the Nummulites species, the engagement of a draughtsman, the contents of a paper read by Williamson at the Royal Microscopic Society concerning Ortbitolina and foraminifera and an invitation to dinner. 9 July 1850
Letter, with envelope, accompanying the return of a signed book which had been sent in error. Discusses a public letter by Falconer accusing Lyell of plagiarism. Refers to an item in the Athenaeum concerning the Abbeville jaw. 18 April 1863
Letter, with envelope, giving the reference, price and outlet for Carpenter's Introduction to the Study of the Foraminifera, details of other works concerning foraminifera, apologies for missing a Geology Society of London meeting due to ill health and a discussion concerning Zoophytes. 30 November 1864.
Letter, thanking Lyell for forwarding some specimens. Descriptions of results in experiments to isolate the Foraminifera Eozoon from these and other specimens. Details of a dispute concerning this with William King and the possible diagrammatic presentation of results at the Geological Society of London when King presents his paper, 09 December 1865.
Letter, with envelope, concerning the existence of the foraminifera Eozoon and a collaboration with Story-Maskelyne of the British Museum to prove this, 27 December 1865.
Letter, with envelope, reporting that Carpenter had been showing Rowney thin sections of Canadian Eozoon, a species of foraminifera to prove its existence to him. Asserts that Story-Maskerlyne and Busk are convinced it exists and that King and Rowney had been studying rocks which were too heavily metamorphosed, 09 January 1866.