Transcripts and extracts by D. Morgan Lewis relating to Welsh hymns and hymntunes. Much of the material is based on printed collections, but some is derived from manuscript sources in the National Library of Wales, such as NLW MSS 78A (holograph hymns of William Williams, Pantycelyn), 1932E (Welsh music collected by John Jenkins, 'Ifor Ceri'), and 1940i & iiA ('Melus-Seiniau Cymru' collected by 'Ifor Ceri'), and NLW, C. M. Archives MSS 5843-5901 (manuscripts of the Reverend John Hughes, Pontrobert).