| Rhif Cyf Amg | BMSS/27356-27364 |
| Teitl | Documents relating mostly to the geology of Anglesey |
| Dyddiad | 20th century |
| Deunydd Cysylltiedig | Earlier material deposited have been catalogued as Bangor Mss 27033-27038 |
| Acquisition | Deposited by Mrs Nigel Conant of Holyhead |