A manuscript in the hand of Moses Williams containing the Interpretation of Dreams from Llanstephan MS 28; and 'Gr. ap kynan twssog kymry a wnaith gyfreth ar y gwyr wrth gerdd' in a seventeenth century hand.
A manuscript in the hand of Moses Williams (pp. 1-4) and another (pp. 5-66) containing a transcript of Kulhwch ac Olwen and of Y Mabinogion from the Red Book of Hergest.
A manuscript in the hand of Moses Williams containing 'Buchedd Collen' (pp. 25-31), 'Hanes Taliesin' (pp. 33-44), 'Keyryd' (p. 77), transcripts from the Black Book of Carmarthen (pp. 1-20, 98-118) and the Book of Taliesin (pp. 79-97), triads taken from 'Y Cwta Cyfarwydd' (p. 45 (see Peniarth MS 50, p. 149)) and from the work of John Jones, Gellilyfdy (p. 62) and other material, some of which relates to Welsh geographical features (pp. 32 (taken from the work of John Jones, Gellilyfdy), 75-76, 121). P. i contains an index of the contents. For p. 1 of this manuscript see Peniarth MS 98b, p. 2; for pp. 1-20 see Peniarth MS 98b, p. 49; for p. 45 see Peniarth MS 50, p. 149. At the end of the section at pp. 4-20 is noted 'O'r Llyfr du o Gaerfyrddin hyd yma; ac o hyn allan o law W. Salsburi medd Roesser Moris.'
A manuscript containing a Welsh grammar. A note in the hand of Moses Williams reads: 'This copy is out of a MS. lent me by R. Mostyn of Penbedw Esqr., which MS. formerly belong'd to Thomas ap Ivan of Hendre Forfydd [i.e. Peniarth MS 157]. Twas compared with the said MS. 29 Julii 1717 ... Twas also collated with another copy that was once in the possession of Huw ab Owen alias Huw Machno.' There are notes by Moses Williams on the text throughout the volume.