The group comprises personal diaries, 1793-1839, small pocket notebooks and almanacks, 1701-1853, of the Hughes family of Gwydir, Llwyn Gronw and Cae'r berllan, and of the Griffith family of Garn, containing memoranda and personal notes of social and work engagements, accounts, family life, health problems, snippets of local and national news, poetry, recipes, household and estate management, weather conditions, journeys, hunting, shooting and fishing, useful addresses, sketches. The memorandum books are more sporadic and miscellaneous in nature than the diaries, where the format is comparatively regular. Many of the volumes contain loose enclosures of various types.

Mae'r gyfres yn cynnwys llyfrau gwersi a nodiadau cyffredinol yn ymwneud â David Bowen a'i deulu.