'I'w Urddas Brenhinol Tywysog Cymru fel arwydd fechan o barch ac edmygedd Cymry godre'r Andes, Archentina', being an address, with autograph signatures, presented to H.R.H. the Prince of Wales [afterwards Edward VIII [1894-1972]] in March 1931 on his visit to Argentina by 'The Pioneers of Cwm Hyfryd', ('Colonia 16 de Octubre') in the Welsh colony in Patagonia. Among the signatories are John D. Evans [1862-1943], 'Arloesydd', and Mihangel ap Iwan [d. 1944].

Papers of Frank H. Cleaver, 1924-1985, mainly accounts, including personal, family and household expenses, 1924-1985; expenses for his work in Argentina, 1929-1931; and summaries of accounts, 1949-1968.

Papers of and acquired by R. Bryn Williams, mainly relating to the Welsh settlement in Patagonia, including a diary of Joseph Seth Jones, one of the first wave of emigrants on the Mimosa to Patagonia, 1865, and correspondence, 1865-1868; correspondence of his brother, Robert Charles Jones, 1867-1877; copy records of the Welsh courts in Y Wladfa, 1872-1881; letters and minute books relating to Vrondeg Baptist Chapel, 1875-1887, Gaiman, 1877-1891, Eglwys Llanddewi, 1891, Eglwys Bryn Gwyn and Cyfarfod Misol Y Wladfa (Calvinistic Methodists), 1881-1955; papers relating to the Centenary Celebrations of the Welsh settlement in Patagonia, 1952-1962; letters from the founders of the Welsh colony, 1866, and from others who had experienced life there; letters to R. Bryn Williams from Patagonia and from Wales relating to Patagonia, [c. 1941-1961]; research notes and manuscripts of books and radio plays by R. Bryn Williams, 1942-1962; miscellaneous records relating to Wales and elsewhere collected by Williams, 1865-1962; papers relating to John S. Williams, 1901-1962; papers and press cuttings on the history, culture and industry of Patagonia, 1869-1962; and typescripts of published and unpublished works, lectures, scripts, etc.