| Reference number | Title | Date |
| EC/1854/15 | Williamson, William Crawford: certificate of election to the Royal Society | |
| IM/Maull/004939 | Williamson, William Crawford | nd |
| NLB/10/249 | Copy letter from an unknown correspondent, to Messrs Edkins & Company | 31 October 1894 |
| NLB/2/15 | Copy letter from Herbert Rix, to Professor William Crawford Williamson, Fellow of the Royal Society | 6 December 1887 |
| NLB/1/538 | Copy letter from Herbert Rix, to Professor William Crawford Williamson, Fellow of the Royal Society | 25 July 1887 |
| NLB/2/64 | Copy letter from Herbert Rix, to Professor William Crawford Williamson, Fellow of the Royal Society | 2 January 1888 |
| NLB/1/712 | Copy letter from Herbert Rix, to Professor William Crawford Williamson, Fellow of the Royal Society | 9 November 1887 |
| NLB/2/442 | Copy letter from Herbert Rix, to Professor William Crawford Williamson, Fellow of the Royal Society | 2 July 1888 |
| NLB/2/802 | Copy letter from Herbert Rix, to Professor William Crawford Williamson, Fellow of the Royal Society | 8 November 1888 |
| NLB/1/711 | Copy letter from an unknown correspondent, to Messrs Whiteman & Bass, 235 High Holborn | 9 November 1887 |
| NLB/2/692 | Copy letter from Herbert Rix, to William Carruthers, Fellow of the Royal Society | 12 October 1888 |
| NLB/2/81 | Copy letter from Herbert Rix, to Professor William Crawford Williamson, Fellow of the Royal Society | 6 January 1888 |
| NLB/3/68 | Copy letter from Herbert Rix, to Professor William Crawford Williamson, Fellow of the Royal Society | 2 March 1889 |
| NLB/4/677 | Copy letter from Herbert Rix, to Professor William Crawford Williamson, Fallowfield, Manchester | 19 September 1890 |
| NLB/4/684 | Copy letter from Herbert Rix, to Professor William Crawford Williamson, Fellow of the Royal Society | 23 September 1890 |
| NLB/3/72 | Copy letter from an unknown correspondent, to Messrs Whiteman & Bass, 235 High Holborn | 4 March 1889 |
| NLB/5/92 | Copy letter from an unknown correspondent, to Messrs Whiteman & Bass, 235 High Holborn, W.C. | 13 March 1891 |
| NLB/4/694 | Copy letter from Herbert Rix, to Professor William Crawford Williamson, Fellow of the Royal Society | 27 September 1890 |
| NLB/4/689 | Copy letter from Herbert Rix, to Professor William Crawford Williamson, Fellow of the Royal Society | 25 September 1890 |
| NLB/6/1074 | Copy letter from an unknown correspondent, to Messrs Whiteman & Bass | 18 October 1892 |
| NLB/3/636 | Copy letter from Herbert Rix, to Messrs Whitesman & Bass | 29 July 1889 |
| NLB/3/527 | Copy letter from an unknown correspondent, to Messrs Whiteman & Bass, 235 High Holborn | 4 July 1889 |
| NLB/3/564 | Copy letter from Herbert Rix, to Messrs Whiteman & Bass, 235 High Holborn | 13 July 1889 |
| NLB/3/531 | Copy letter from Herbert Rix, to [John William Strutt] Lord Rayleigh, [Royal Society] | 4 July 1889 |
| NLB/3/705 | Copy letter from [Herbert Rix], to Messrs Whiteman & Bass, 235 High Holborn | 20 September 1889 |
| NLB/3/682 | Copy letter from Alfred H White, to Messrs Whiteman & Bass, High Holborn | 11 September 1889 |
| NLB/3/665 | Copy letter from Alfred H White, to Dr Michael Foster, Secretary, Royal Society | 10 August 1889 |
| NLB/3/750 | Copy letter from Herbert Rix, to Professor William Crawford Williamson, Fellow of the Royal Society | 30 September 1889 |
| NLB/6/556 | Copy letter from Hernert Rix, to Professor William Crawford Williamson, Fellow of the Royal Society | 31 May 1892 |
| NLB/6/1130 | Copy letter from Herbert Rix, to Professor William Crawford Williamson, Fellow of the Royal Society | 29 October 1892 |
| NLB/6/595 | Copy letter from Herbert Rix, Professor William Crawford Williamson, Fellow of the Royal Society | 8 June 1892 |
| NLB/5/52 | Copy letter from Herbert Rix, to Sir Joseph Dalton Hooker, Fellow of the Royal Society | 28 February 1891 |
| NLB/5/83 | Copy letter from an unknown correspondent, to Messrs Whiteman & Bass, 235 High Holborn | 10 March 1891 |
| NLB/6/958 | Copy letter from Herbert Rix, to Messrs Whiteman & Bass | 26 September 1892 |
| NLB/6/954 | Copy letter from Herbert Rix, to Messrs Harrison & Sons | 26 September 1892 |
| NLB/6/896 | Copy letter from Theodore E James, to Professor Frederick Orpen Bower, Fellow of the Royal Society | 15 August 1892 |
| NLB/7/276 | Copy letter from Herbert Rix, to Professor William Crawford Williamson, Fellow of the Royal Society | 11 January 1893 |
| NLB/6/944 | Copy letter from Herbert Rix, to Messrs Whiteman & Bass, 235 High Holborn | 21 September 1892 |
| NLB/6/934 | Copy letter from Herbert Rix, to Professor [William Crawford] Williamson, Fellow of the Royal Society | 21 September 1892 |
| NLB/6/897 | Copy letter from Theodore E James, to Professor Michael Foster | 15 August 1892 |
| NLB/6/948 | Copy letter from Howard Rix, to Lord Rayleigh [John William Strutt] | 23 September 1892 |
| NLB/5/223 | Copy letter from Herbert Rix, to Messrs Whiteman & Bass, 235 High Holborn, W.C. | 17 April 1891 |
| NLB/5/242 | Copy letter from Herbert Rix, to Professor William Crawford Williamson, Fellow of the Royal Society | 18 April 1891 |
| NLB/5/225 | Copy letter from Herbert Rix, to Professor William Crawford Williamson, Fellow of the Royal Society | 17 April 1891 |
| NLB/5/276 | Copy letter from an unknown correspondent, to Messrs Whiteman & Bass, 235 High Holborn | 27 April 1891 |
| NLB/7/291 | Copy letter from Herbert Rix, to Messrs West, Newman & Company | 13 January 1893 |
| NLB/9/80 | Copy letter from Herbert Rix, to Professor William Crawford Williamson, Fellow of the Royal Society | 22 March 1894 |
| NLB/7/294 | Copy letter from Herbert Rix, to Professor William Crawford Williamson, Fellow of the Royal Society | 3 January 1893 |
| NLB/7/292 | Copy letter from Herbert Rix, to Messrs Whiteman & Bass | 13 January 1893 |
| NLB/7/341 | Copy letter from Herbert Rix, to Messrs Whiteman & Bass | 25 January 1893 |
| NLB/7/771 | Copy letter from Herbert Rix, to Professor William Crawford Williamson, Fellow of the Royal Society | 24 April 1893 |
| NLB/8/16 | Copy letter from Herbert Rix, to Professor William Crawford Williamson, Fellow of the Royal Society | 29 June 1893 |
| NLB/7/763 | Copy letter from Herbert Rix, to Professor William Crawford Williamson, Fellow of the Royal Society | 21 April 1893 |
| NLB/7/893 | Copy letter from Herbert Rix, to Professor William Crawford Williamson, Fellow of the Royal Society | 19 May 1893 |
| NLB/10/351 | Copy letter from an unknown correspondent, to Messrs Edkins & Company | 12 November 1894 |
| NLB/10/511 | Copy letter from an unknown correspondent, to Messrs Edkins & Company | 7 December 1894 |
| NLB/11/427 | Copy letter from an unknown correspondent, to Messrs Harrison & Sons | 26 June 1895 |
| NLB/11/406 | Copy letter from Herbert Rix, to Herbert C Williamson, 43 Elms Road, Clapham Common | 24 June 1895 |
| NLB/11/334 | Copy letter from Herbert Rix, to Dr Dukinfield Henry Scott, Fellow of the Royal Society | 6 June 1895 |
| NLB/11/713 | Copy letter from an unknown correspondent, to Messrs Edkins | 23 September 1895 |
| NLB/11/808 | Copy letter from Herbert Rix, to Mrs [William Crawford] Williamson, 43 Elms Road, Clapham Common, S.W. | 9 October 1895 |
| NLB/11/835 | Copy letter from an unknown correspondent, to Messrs Edkins & Company | 15 October 1895 |
| NLB/9/830 | Copy letter from Herbert Rix, to Professor William Crawford Williamson, Fellow of the Royal Society | 17 July 1894 |
| RR/9/417 | Referee's report by Joseph Dalton Hooker, on a paper 'On the organisation of the fossil plants of the coal-measures. Heterangium Tiliœoides (Will.) and Kaloxylon Hookeri' by William Crawford Williamson | 27 February 1887 |
| NLB/6/898 | Copy letter from Theodore E James, to Lord Rayleigh [John William Strutt] | 15 August 1892 |
| RR/7/148 | Referee's report by Charles James Fox Bunbury, on a paper 'Supplementary observations on lepidodendra' by William Crawford Williamson | 4 October 1871 |
| RR/7/355 | Referee's report by Joseph Dalton Hooker, on a paper 'On the organization of the fossil plants of the coal-measures. Part VI - Ferns' by William Crawford Williamson | 13 June 1874 |
| RR/7/150 | Referee's report by Robert Etheridge, on a paper 'On the organization of the fossil plants of the coal-measures - Part II. Lycopodiaceae: lepidodendra and sigillariae' by William Crawford Williamson | 24 November 1871 |
| RR/7/149 | Referee's report by Robert Etheridge, on a paper 'On the organization of the fossil plants of the coal-measures - Part II. Lycopodiaceae: lepidodendra and sigillariae' by William Crawford Williamson | 22 November 1871 |
| RR/7/281 | Referee's report by Robert Etheridge, on a paper 'On the organization of the fossil plants of the coal-measures. Part V - Asterophyllites' by William Crawford Williamson | 5 November 1873 |
| RR/7/146 | Referee's report by William Carruthers, on a paper 'On the organization of the fossil plants of the coal-measures - Part I. Catamites' by William Crawford Williamson | 14 June 1871 |
| RR/7/215 | Referee's report by Charles James Fox Bunbury, on a paper 'On the organization of the fossil plants of the coal-measures - Part III. Lycopodiaceae (continued)' by William Crawford Williamson | 4 May 1872 |
| RR/7/145 | Referee's report by Charles James Fox Bunbury, on a paper 'On the organization of the fossil plants of the coal-measures - Part I. Catamites' by William Crawford Williamson | 3 March 1871 |
| RR/7/280 | Referee's report by Charles James Fox Bunbury, on a paper 'On the organization of the fossil plants of the coal-measures. Part V - Asterophyllites' by William Crawford Williamson | 22 July 1873 |
| RR/8/75 | Referee's report by William Carruthers, on a paper 'On the organization of the fossil plants of the coal-measures. —Part IX' by William Crawford Williamson | 14 August 1877 |
| RR/8/216 | Second referee's report by Joseph Dalton Hooker, on a paper 'On the organization of the fossil plants of the coal-measures.—Part X. Including an examination of the supposed radiolarians of the carboniferous rocks' by William Crawford Williamson | 20 August 1879 |
| RR/7/500 | Referee's report by Joseph Dalton Hooker, on a paper 'On the organization of the fossil plants of the coal-measures. Part VII - Myelopteris, psaronius, and kaloxylon' by William Crawford Williamson | 19 August 1876 |
| RR/9/102 | Referee's report by Joseph Dalton Hooker, on a paper 'On the organization of the fossil plants of the coal-measures. Part XII' by William Crawford Williamson | 26 October 1882 |
| RR/8/74 | Referee's report by Joseph Dalton Hooker, on a paper 'On the organization of the fossil plants of the coal-measures. —Part IX' by William Crawford Williamson | 19 June 1877 |
| RR/9/103 | Referee's report by William Carruthers, on a paper 'On the organization of the fossil plants of the coal-measures. Part XII' by William Crawford Williamson | 16 December 1882 |
| RR/11/103 | Referee's report by William Carruthers, on a paper 'On the organisation of the fossil plants of the coal-measures.—Part XVIII' by William Crawford Williamson | 25 February 1891 |
| RR/10/111 | Referee's report by William Carruthers, on a paper 'On the organisation of the fossil plants of the coal-measures.--Part XV' by William Crawford Williamson | 19 October 1888 |
| RR/10/112 | Referee's report by Joseph Dalton Hooker, on a paper 'On the organisation of the fossil plants of the coal-measures.--Part XV' by William Crawford Williamson | 20 November 1888 |
| RR/11/220 | Letter from William Carruthers on a paper 'On the organization of the fossil plants of the coal-measures. Part XIX' by William Crawford Williamson | 30 June 1892 |
| RR/11/222 | Referee's report by Frederick Orpen Bower on a paper 'On the organization of the fossil plants of the coal-measures. Part XIX' by William Crawford Williamson | 11 August 1892 |
| RR/11/104 | Referee's report by Joseph Dalton Hooker, on a paper 'On the organisation of the fossil plants of the coal-measures.—Part XVIII' by William Crawford Williamson | 1 March 1891 |
| RR/11/221 | Referee's report by William Carruthers on a paper 'On the organization of the fossil plants of the coal-measures. Part XIX' by William Crawford Williamson | 30 June 1892 |
| RR/12/264 | Referee's report by Joseph Dalton Hooker, on a paper 'Further observations on the organization of the fossil plants of the coal- measures. —Part I. Calamites, Calamostachys, and Sphenophyllum' by William Crawford Williamson and Dukinfield Henry Scott | 20 January 1894 |
| RR/12/265 | Referee's report by William Carruthers, on a paper 'Further observations on the organization of the fossil plants of the coal- measures. —Part I. Calamites, Calamostachys, and Sphenophyllum' by William Crawford Williamson and Dukinfield Henry Scott | 28 February 1894 |
| RR/11/219 | Referee's report by Joseph Dalton Hooker, on a paper 'On the organization of the fossil plants of the coal-measures. Part XIX' by William Crawford Williamson | 24 March 1892 |
| RR/12/406 | Referee's report by Joseph Dalton Hooker, on a paper 'Further observations on the organization of the fossil plants of the coal-measures.—Part II. The roots of Calamites' by William Crawford Williamson and Dukinfield Henry Scott | 5 January 1895 |
| RR/12/409 | Letter from Joseph Dalton Hooker, on a paper 'Further observations on the organization of the fossil plants of the coal-measures.-Part III. Lygnodendron and Heterangium' by William Crawford Williamson and Dukinfield Henry Scott to Michael Foster | [1895] |
| RR/9/421 | Third letter from William Crawford Williamson, on his paper 'On the organisation of the fossil plants of the coal-measures. Heterangium Tilioeoides (Will.) and Kaloxylon Hookeri' to the Secretary of the Royal Society | 7 May 1887 |
| RR/9/104 | Referee's report by William Carruthers, on a paper 'On the organization of the fossil plants of the coal-measures. Part XII' by William Crawford Williamson | 16 December 1882 |
| RR/9/422 | Fourth letter from William Crawford Williamson, on his paper 'On the organisation of the fossil plants of the coal-measures. Heterangium Tilioeoides (Will.) and Kaloxylon Hookeri' to the Secretary of the Royal Society | 15 May 1887 |
| RR/8/215 | Referee's report by Joseph Dalton Hooker, on a paper 'On the organization of the fossil plants of the coal-measures.—Part X. Including an examination of the supposed radiolarians of the carboniferous rocks' by William Crawford Williamson | 19 June 1877 |
| RR/10/109 | Referee's report by Joseph Dalton Hooker, on a paper 'On the organisation of the fossil plants of the coal-measures.—Part XIII. Heterangium tiliaeoides (Williamson) and Kaloxylon hookeri' by William Crawford Williamson | 25 June 1887 |
| RR/7/354 | Referee's report by Charles James Fox Bunbury, on a paper 'On the organization of the fossil plants of the coal-measures. Part VI - Ferns' by William Crawford Williamson | 11 May 1874 |
| RR/7/279 | Referee's report by Robert Etheridge, on an appendix to a paper 'On the organization of the fossil plants of the coal-measures. Part IV - Dictyoxlon, lyginodendron, and heterangium' by William Crawford Williamson | 10 July 1873 |
| RR/7/427 | Letter from Charles James Fox Bunbury, on a paper 'On the organization of the fossil plants of the coal-measures. Part VII - Myelopteris, psaronius, and kaloxylon' by William Crawford Williamson to the Secretary of the Royal Society | 25 June 1875 |
| RR/8/264 | Referee's report by Joseph Dalton Hooker, on a paper 'On the organization of the fossil plants of the coal-measures.—Part XI' by William Crawford Williamson | 28 September 1880 |
| RR/8/266 | Second referee's report by William Carruthers, on a paper 'On the organization of the fossil plants of the coal-measures.—Part XI' by William Crawford Williamson | 27 October 1880 |
| MS/426/471 | Note of a letter from [the Secretaries of] the Royal Society; to various Fellows | 15 July 1852 |
| NLB/4/713 | Copy letter from Herbert Rix, to Professor William Crawford Williamson | 2 October 1890 |
| NLB/6/509 | Copy letter from Herbert Rix, to Professor Michael Foster | 26 May 1892 |
| NLB/5/22 | Copy letter from Michael Foster, to Professor William Crawford Williamson, [Fellow of the Royal Society] | 20 February 1891 |
| NLB/10/117 | Copy letter from Herbert Rix, to Messrs Edkins & Company | 2 October 1894 |
| NLB/11/777 | Copy letter from Herbert Rix, to Messrs Edkins & Company | 3 October 1895 |
| NLB/10/530 | Copy letter from an unknown correspondent, to Messrs Edkins and Company | 12 December 1894 |
| NLB/11/312 | Copy letter from Herbert Rix, to Professor Michael Foster | 31 May 1895 |
| MC/28/242 | Letter from [Dukinfield Henry] Scott, East Oakley House, Basingstoke, to Mr [Robert] Harrison, [Royal Society] | 28 January 1913 |
| RR/7/147 | Referee's report by Charles James Fox Bunbury, on a paper 'On the organization of the fossil plants of the coal-measures - Part II. Lycopodiaceae: lepidodendra and sigillariae' by William Crawford Williamson | 14 August 1871 |
| RR/9/419 | Letter from William Crawford Williamson, on his paper 'On the organisation of the fossil plants of the coal-measures. Heterangium Tiliœoides (Will.) and Kaloxylon Hookeri' to the Secretary of the Royal Society | 30 March 1887 |
| NLB/5/46 | Copy letter from Herbert Rix, to Professor William Crawford Williamson, [Fellow of the Royal Society] | 26 February 1891 |
| NLB/6/928 | Copy letter from Herbert Rix, to Professor Michael Foster | 19 September 1892 |
| NLB/9/237 | Copy letter from Herbert Rix, to Professor William Crawford Williamson, Fellow of the Royal Society | 20 April 1894 |
| NLB/11/58 | Copy letter from Herbert Rix, to Messrs Edkins & Company | 8 April 1895 |
| NLB/11/57 | Copy letter from Herbert Rix, to Dr Michael Foster, Secretary, Royal Society | 8 April 1895 |
| RR/10/110 | Referee's report by William Carruthers, on a paper 'On the organisation of the fossil plants of the coal-measures.—Part XIII. Heterangium tiliaeoides (Williamson) and Kaloxylon hookeri' by William Crawford Williamson | 25 October 1887 |
| RR/11/105 | Referee's report by William Carruthers, on a paper 'On the organisation of the fossil plants of the coal-measures.—Part XVIII' by William Crawford Williamson | 1 August 1890 |
| RR/9/418 | Referee's report by William Carruthers, on a paper 'On the organisation of the fossil plants of the coal-measures. Heterangium Tiliœoides (Will.) and Kaloxylon Hookeri' by William Crawford Williamson | 23 February 1887 |
| PT/36/7 | Paper, 'On the microscopic structure of the scales and dermal teeth of some ganoid and placoid fish' by W C [William Crawford] Williamson | 24 March 1849 |
| RR/2/264 | Referee's report by Richard Owen, on a paper 'Investigations into the structure and development of the scales and bones of fishes' by William Crawford Williamson | 4 September 1850 |
| PT/75/3/10 | Paintings, 'A Rotalia with remains of the soft parts in the shell' by Jos [Joseph] Dinkel | [1846] |
| PT/42/14 | Paper, 'Investigations into the structure and developement [sic] of the scales and bones of fishes' by W C [William Crawford] Williamson | [1850] |
| RR/8/269 | Letter from Joseph Dalton Hooker, to George Gabriel Stokes, regarding a paper 'On the organization of the fossil plants of the coal-measures.—Part XI' by William Crawford Williamson | 28 September 1880 |
| RR/10/314 | Referee's report by William Carruthers, on a paper 'On the organisation of the fossil plants of the coal-measures.—Part XVI' by William Crawford Williamson | 6 June 1889 |
| RR/10/313 | Referee's report by Joseph Dalton Hooker, on a paper 'On the organisation of the fossil plants of the coal-measures.—Part XVI' by William Crawford Williamson | 18 April 1889 |
| RR/12/266 | Referee's report by Isaac Bayley Balfour, on a paper 'Further observations on the organization of the fossil plants of the coal- measures. —Part I. Calamites, Calamostachys, and Sphenophyllum' by William Crawford Williamson and Dukinfield Henry Scott | 16 April 1894 |
| RR/12/407 | Referee's report by Isaac Bayley Balfour, on a paper 'Further observations on the organization of the fossil plants of the coal-measures.—Part II. The roots of Calamites' by William Crawford Williamson and Dukinfield Henry Scott | 3 April 1895 |
| MC/9/387 | Letter from W C [William Crawford] Williamson, Fallowfield, to Dr [William] Sharpey, [Secretary of the Royal Society] | 8 June 1872 |
| MC/9/548 | Letter from W C [William Crawford] Williamson, Fallowfield, to the Royal Society | 7 May 1873 |
| MC/9 | Volume 9 of miscellaneous correspondence regarding business matters, sent to the Royal Society | 1870-June 1873 |
| MC/10/386 | Letter from W C [William Crawford] Williamson, Owen's College, Manchester, to the Royal Society | 29 April 1876 |
| MC/10 | Volume 10 of miscellaneous correspondence regarding business matters, sent to the Royal Society | July 1873-1876 |
| MC/11/228 | Letter from W C [William Crawford] Williamson, Fallowfield, to the Royal Society | 23 June 1878 |
| RR/2/263 | Referee's report by Gideon Algernon Mantell, on a paper 'Investigations into the structure and development of the scales and bones of fishes' by William Crawford Williamson | 2 July 1850 |
| MC/11/329 | Letter from W C [William Crawford] Williamson, Bradford, to [Walter] White, [Assistant Secretary of the Royal Society] | 7 April 1879 |
| MC/11 | Volume 11 of miscellaneous correspondence regarding business matters, sent to the Royal Society | 1877-1879 |
| MC/12/3 | Letter from W C [William Crawford] Williamson, Fallowfield, Manchester, to Professor [George Gabriel] Stokes, [Secretary of the Royal Society] | 9 January 1880 |
| MC/12/51 | Letter from W C [William Crawford] Williamson, Fallowfield, to [Thomas Henry] Huxley, [Secretary of the Royal Society] | 2 June 1880 |
| MC/12/82 | Letter from William C [Crawford] Williamson, Fallowfield, to [Walter] White, [Assistant Secretary of the Royal Society] | 22 July 1880 |
| MC/12 | Volume 12 of miscellaneous correspondence regarding business matters, sent to the Royal Society | 1880-1883 |
| RR/11/223 | Second referee's report by Frederick Orpen Bower on a paper 'On the organization of the fossil plants of the coal-measures. Part XIX' by William Crawford Williamson | 9 September 1892 |
| RR/12/408 | Referee's report by Joseph Dalton Hooker, on a paper 'Further observations on the organization of the fossil plants of the coal-measures.-Part III. Lygnodendron and Heterangium' by William Crawford Williamson and Dukinfield Henry Scott | 14 June 1895 |
| PP/10/3 | Paper, 'Note on Lepidodendron Harcourtii and L fuliginosum (Will)' by William Crawford Williamson | 1886 |
| MC/14/6 | Letter from [William Crawford] Williamson, Manchester, to [Walter] White | 18 January 1885 |
| RR/7/216 | Referee's report by Robert Etheridge, on a paper 'On the organization of the fossil plants of the coal-measures - Part III. Lycopodiaceae (continued)' by William Crawford Williamson | 26 May 1872 |
| RR/7/277 | Referee's report by Charles James Fox Bunbury, on a paper 'On the organization of the fossil plants of the coal-measures. Part IV - Dictyoxlon, lyginodendron, and heterangium' by William Crawford Williamson | 18 February 1873 |
| RR/7/278 | Referee's report by Robert Etheridge, on a paper 'On the organization of the fossil plants of the coal-measures. Part IV - Dictyoxlon, lyginodendron, and heterangium' by William Crawford Williamson | 8 April 1873 |
| RR/7/501 | Referee's report by William Carruthers, on a paper 'On the organization of the fossil plants of the coal-measures. Part VII - Myelopteris, psaronius, and kaloxylon' by William Crawford Williamson | 23 October 1876 |
| RR/8/265 | Referee's report by William Carruthers, on a paper 'On the organization of the fossil plants of the coal-measures.—Part XI' by William Crawford Williamson | 27 October 1880 |
| RR/8/267 | Letter from George Gabriel Stokes, to William Crawford Williamson, regarding a paper 'On the organization of the fossil plants of the coal-measures.—Part XI' by William Crawford Williamson | 30 October 1880 |
| RR/8/268 | Letter from William Crawford Williamson, to George Gabriel Stokes, regarding a paper 'On the organization of the fossil plants of the coal-measures.—Part XI' by William Crawford Williamson | 31 October 1881 |
| RR/9/420 | Second letter from William Crawford Williamson, on his paper 'On the organisation of the fossil plants of the coal-measures. Heterangium Tilioeoides (Will.) and Kaloxylon Hookeri' to the Secretary of the Royal Society | 5 April 1887 |
| RR/10/315 | Letter from William Crawford Williamson, to John William Strutt, 3rd Baron Rayleigh, regarding a paper 'On the organisation of the fossil plants of the coal-measures.—Part XVI' by William Crawford Williamson | 27 November 1889 |
| RR/10/395 | Referee's report by Joseph Dalton Hooker, on a paper 'On the organisation of the fossil plants of the coal-measures.—Part XVII' by William Crawford Williamson | 10 March 1890 |
| RR/12/410 | Referee's report by Isaac Bayley Balfour, on a paper 'Further observations on the organization of the fossil plants of the coal-measures.-Part III. Lygnodendron and Heterangium' by William Crawford Williamson and Dukinfield Henry Scott | 29 July 1895 |
| PP/24/10 | Paper, 'The root of Lyginodendron Oldhamium, Will' by William Crawford Williamson and Dukinfield Henry Scott | 1894 |
| MC/15/132 | Letter from [William Crawford] Williamson, The Owen's College, Manchester, to [Michael] Foster | 21 January 1891 |
| PP/23/29 | Appendix, 'Correction of an error of observation in part XIX of the author’s memoirs on the organisation of the fossil plants of the coal measures' by William Crawford Williamson | 1894 |
| MC/15/143 | Letter from [William Crawford] Williamson, Fallowfield, Manchester, to [Michael] Foster | 5 February 1891 |
| MC/16/12 | Letter from [William Crawford] Williamson, 43 Elms Road, Clapham Common, to [Michael] Foster | 11 February 1893 |
| MC/14/13 | Letter from [William Crawford] Williamson, Fallow Field, to [Walter] White | 30 January 1885 |
| MC/14 | Volume 14 of miscellaneous correspondence regarding business matters, sent to the Royal Society | 1885-1888 |
| MC/15 | Volume 15 of miscellaneous correspondence regarding business matters, sent to the Royal Society | 1889-1892 |
| MC/16 | Volume 16 of miscellaneous correspondence regarding business matters, sent to the Royal Society | 1893-1896 |
| MC/28/243 | Letter from [Dukinfield Henry] Scott, East Oakley House, Basingstoke, to Mr [Robert] Harrison, [Royal Society] | 6 February 1913 |