A yellow gold and enamel Jump Hour open-faced pocket watch

A yellow gold and enamel Jump Hour open-faced pocket watch, c.1830, engine-turned dial, aperture and 12 o'clock for Jump Hour display, front and reverse of case decorated with black and gold foliate enamel decoration, the back case centred with a polychrome enamel butterfly, unsigned movement, inner case 429 38342, case 42mm, box