Twelve notebooks in the hand of Watcyn Uther Williams of transcripts of the poetry of Sion Tudur and three portfolios of copies of cywyddau by him. There is also an item described as an introduction to the first volume of the poems of Sion Tudur which includes a brief criticism of the character of the poems. Also, photocopies and tracings of original manuscripts; letters to Watcyn Uther Williams from such people as W. Ambrose Bebb and Sir Ifor Williams as well as note books belonging to Watcyn Uther Williams whilst he was a student at Cardiff with notes on Welsh grammar and history.
In addition, the collection has a few letters addressed to Pedr Hir from various correspondents, together with a bundle of notes on sermons by him.