A collection of historical tracts transcribed by John Thomas from manuscripts of Evan Evans ('Ieuan Brydydd Hir') - a transcript of the Charter granted by Henry VII to the inhabitants of North Wales, 1507; a translation of De Bardis Britannicis Dissertatio, 1760; extracts from correspondence concerning Welsh antiquities between Lewis Morris, Edward Richard, Dr Philips, Blaenpant, and Samuel Pegge, 1759-1760; a transcript of Sir John Wynne's History of the Gwydir Family; and a copy of the pedigree of the families mentioned in that work brought down to 1764, and taken from a manuscript in the possession of Lewis Owen, curate of Llanllechid.

A composite volume mostly in the hand of Evan Evans (Ieuan Fardd) containing transcripts of correspondence between Lewis Morris, Edward Richard, James Phillips and Samuel Pegge (see Cambrian Register, Vol. i, p. 357) (ff. 1-36); a copy of Morgan Jones's letter from New York, 10 March 1685/6, relating to Welsh Indians (ff. 41-43) (see the Gentleman's Magazine, 1740, and NLW MS 2577B); extracts from a letter of Griffith Roberts (ff. 54-57) and from a commonplace book of Robert Vaughan, Hengwrt (ff. 193-208); proverbs in Welsh and Latin (ff. 58-63); autograph proposals for printing a book of poetry (later 'Gorchestion Beirdd Cymru') to be edited by Ieuan Fardd and Rhys (Rice) Jones and published by David Jones, Trefriw (ff. 89-92); a note on manuscripts in the Mostyn library (ff. 98-99); a copy of Henry VII's charter of North Wales (f. 100); poetry (ff. 112-113, 116-124, 209-212); the Introduction to Lewis Morris et al's Celtic Remains, and copies of letters from Lewis Morris to Robert Vaughan and others (ff. 125-164); a copy of Annals of Wales by Robert Vaughan (ff. 165-192) (see Mostyn MS 136); chronicles, etc. with notes by Lewis Morris (ff. 213-239); further extracts from various sources; etc.