Manuscripts of works by Wmffre Dafydd ab Ifan, Llanbrynmair, [1620x1660], and others; accounts, rentals and chapel records relating to Llanuwchllyn, Llandderfel and Llandrillo-yn-Edeirnion, and the Glanllyn estate, Merionethshire, 1785-1878; commonplace books, 1717-1824; letters, mainly to Ivan T. Davies, from O. M. Edwards, T. E. Ellis, Professor Kuno Meyer and others, 1869-1929; and other items relating to the Rev. Ivan T. Davies, 1872-1969.
Letters, 1899-1920, in Welsh and English, to Caradoc Mills (Sigma), Llanrwst, author of books and articles on scientific subjects, relating mainly to his published articles. The correspondents include Ifan ab Owen Edwards (1) 1920, Owen M. Edwards (23) 1900-1909 and undated, Archibald Geikie (1) 1902, Robert Owen Hughes (Elfyn) (3) 1904, Eleazer Roberts (2) 1905-1906, Principal T. F. Roberts (1) 1907, and W. W. Watts (2) 1902 and 1908. Also included is a typescript copy of the Board of Education Inspector's report on Evening Continuation Classes at Llanrwst, 1907-1908, in which reference is made to Caradoc Mills.
Twelve letters, 1900-1902, from Edward Thomas to Sir Owen M. Edwards, his erstwhile tutor at Lincoln College, Oxford, written shortly after Thomas had left university, their main purpose being to ask for guidance in seeking employment; they also reflect his attachment to Wales and his interest in the Welsh language.
The editor's own set of Cymru (O. M. Edwards), Vols. 1-44, 1891-1913 containing manuscript notes, some original manuscripts of contributions and letters by correspondents.
