A pocket book used originally, 1669-1675, by Richard Myddelton (afterwards 3rd bart) (1655-1716) to record accounts relating to lead works at Ysceifiog, Penrhyn-du, Maesafon and Penypwll, and later, 1694-1716, used by Robert Myddelton (1678-1733) of Chirk Castle to record miscellaneous financial and other memoranda; also a note on the manor of Langhorne, Cheshire by Sir William Myddelton, 4th bart (1694-1718).