Papers, 1781-1815, relating mainly to the Mostyn estates of Plas Hen, Caernarvonshire, and Corsygedol, Merioneth, including accounts, lists of disbursements, etc., a valuation of the Corsygedol estate, 1808, a copy of the assessments of the hundred of Eifionydd, 1794, and a pedigree, compiled in the nineteenth century, of the families associated with Wern, Caernarvonshire, and Peniarth, Hengwrt, and Rhug, Merioneth.