A volume in the hand of William Williams (1738-1817), Llandygái, co. Caernarfon, author, antiquary, and official of the Cae-braich-y-cafn slate quarry, containing accounts and memoranda, 1778-1791 (ff. 1 verso-34), including particulars of payments to servants and labourers, 1778-1789, churchwarden's accounts, 1778-1780, and accounts, 1779-1781, relating to the 'Bangor Building'. Also included are draft letters, 1807-1809, mostly addressed to the Rev. Dr Samuel Bulkeley (d. 1809), Prebendary of Bristol, and relating mainly to the building of a schoolhouse at Coedana, Anglesey (ff. 35 verso-76 verso, inverted text), and notes in Welsh and English (ff. 77-82 verso, inverted text).