Old Iron Works, Mells (Fussells' Lower Works) (grid reference ST738488) is a 0.25 hectare biological Site of Special Scientific Interest, in the Wadbury Valley, south of the village of Mells in Somerset, notified in 1987.

The block of buildings adjacent to the entrance is listed Grade II* and most of the rest of the site is a Scheduled Ancient Monument.

The land on which the Lower Works were built was leased by John Horner (an alleged descendant of Little Jack Horner) to James Fussell III of Stoke Lane, on 25 December 1744, to erect "a good, firme and substantiall Mill or Mills for Grinding Edge Tools and forging Iron plates".

[6] Tools produced by Fussells were exported to Europe and America, and the family expanded its activities to include coal mining and banking, with the business issuing its own banknotes at one stage.

[5] The business declined towards the end of the 19th century, due in part to a failure to convert from water to steam power until a late stage, and also to the collapse of English agriculture in the 1870s.