The collection contains letters written to R. Peris Williams from various individuals; addresses and notebooks on religious matters such as the attempt to lift the debt owed by Henryd Chapel, Conwy, Caernarfonshire. Also, a few Eisteddfod adjudications, 1867 - 1878 and his own poetical works, 1849 - 1855 as well as two diaries written by him whilst serving as Chaplain in the First World War, 1915 - 1917 and details on the death of Hedd Wyn in 1917.
There is a large section of papers belonging and relating to Gwalchmai. Papers regarding his career as a minister and preacher collated most probably by R. Peris Williams for his memoir on Gwalchmai. Also, a large part of the collection is taken up by letters written to Gwalchmai from various correspondents, family and friends, poets and writers. They provide an insight into the life and interests of the literary men of the Victorian age in Wales and reveal a great deal about religious matters.
Other material, include, collections of hymns; sermons preached by Emrys, 1854-1856; sailing book, 1884-1885 of the Enterprise, captained by George Lewis; diary of Ceiriog as a station master in 1872; autobiography of Rev. Samuel Evans, Llandegla, Denbighshire, 1900 and essays on philology given to Gwallter Mechain by Dr Karl Meyer of Germany, 1844.