| RefNo | Title | Date |
| EC/1815/08 | Fitton, William Henry: certificate of election to the Royal Society | |
| MS/709/20 | Letter from William Henry Fitton, 53 Upper Harley Street, to James [De Carle] Sowerby, 2 Mead Place, Lambeth | 6 July 1827 |
| MS/709/21 | Letter from William Henry Fitton, Highwood Hill, to [James De Carle] Sowerby, 5 Camden Terrace West, Camden Town | 20 May 1835 |
| MS/257/2/155 | Letter from William Henry Fitton to James Clark Ross | 21 June 1839 |
| DM/1/20 | Letter from WH Fitton, Brasted, Somerset, to P M Roget | 10 March 1831 |
| MC/1/266 | Letter from [William] Henry Fitton, 53 Upper Harley Street, to Dr. [Peter Mark] Roget, Secretary of the Royal Society | 22 December 1830 |
| RR/1/157 | Referee's report by William Henry Fitton, on a paper 'Geological remarks on Kerguelen's Land' by R McCormick | 16 June 1841 |
| IM/Maull/001423 | Fitton, William Henry | 06 June 1860 |
| MC/1 | Volume 1 of miscellaneous correspondence regarding business matters, sent to the Royal Society | 1800-1831 |
| RR/1/162 | Referee's report by William Henry Fitton, on a paper 'Memoir on a portion of the lower jaw of the iguanodon, and on the remains of the hylaeosaurus and other saurians, discovered in the strata of Tilgate Forest, in Sussex' by Gideon Algernon Mantell | 10 May 1841 |
| HS/7/233 | Letter, from William Henry Fitton to Sir John Herschel, dated at Highwoodhill, Hendon | 8 October 1831 |
| HS/7/241 | Letter, from William Henry Fitton to Sir John Herschel | 1827 |
| HS/7/230 | Letter, from William Henry Fitton to Sir John Herschel, dated at 53 Upper Harley St. | 5 April 1829 |
| HS/7/242 | Letter, from William Henry Fitton to Sir John Herschel, dated at 4 Sussex Gardens | 6 February 1858 |
| HS/7/227 | Letter, from William Henry Fitton to Sir John Herschel, dated at 53 Upper Harley St. | 24 December 1827 |
| HS/7/232 | Letter, from William Henry Fitton to Sir John Herschel, dated at Geological Society | 12 March 1832 |
| HS/7/240 | Letter, from William Henry Fitton to Sir John Herschel, dated at 18 Norfolk Crescent | 2 August 1855 |
| HS/7/225 | Letter, from William Henry Fitton to Sir John Herschel, dated at Tanhurst near Dorking | 7 September 1827 |
| HS/7/229 | Letter, from William Henry Fitton to Sir John Herschel, dated at 53 Upper Harley St. | 14 August 1828 |
| HS/7/238 | Letter, from William Henry Fitton to Sir John Herschel, dated at Bloomfield Lodge | 10 June 1840 |
| HS/7/239 | Letter, from William Henry Fitton to Sir John Herschel, dated at Wandsworth | 2 August 1844 |
| HS/7/228 | Letter, from William Henry Fitton to Sir John Herschel, dated at 53 Upper Harley St. | 5 August 1828 |
| HS/7/237 | Letter, from William Henry Fitton to Sir John Herschel, dated at Bloomfield Lodge | 3 January 1840 |
| HS/7/244 | Incomplete letter, from William Henry Fitton to Sir John Herschel | undated |
| HS/7/243 | Letter, from William Henry Fitton to Sir John Herschel | 1838 |
| HS/7/226 | Letter, from William Henry Fitton to Sir John Herschel, dated at 53 Upper Harley St. | 24 October 1827 |
| HS/7/236 | Letter, from William Henry Fitton to Sir John Herschel, dated at Bloomfield Lodge | 5 October 1839 |
| HS/19/53 | Letter, from Sir John Herschel to William Henry Fitton, dated at Slough | 14 May 1828 |
| HS/25/1/9 | Copy letter, from Sir John Herschel to William Henry Fitton, dated at Slough | 18 October 1830 |
| HS/27/13 | Letter, from William Henry Fitton to Sir John Herschel | 1826-11-23 or earlier |
| HS/25/7/5 | Copy letter, from Sir John Herschel to William Henry Fitton, dated at Collingwood | 20 February 1847 |
| HS/7/231 | Letter, from William Henry Fitton to Sir John Herschel, dated at 53 Upper Harley St. | 18 December 1830 |
| HS/7/234 | Letter, from William Henry Fitton to Sir John Herschel, dated at Geological Society | 19 December 1836 |
| HS/7/235 | Letter, from William Henry Fitton to Sir John Herschel, dated at Bloomfield Lodge | 27 September 1838 |