St Marys Primary School Including Thornhill

St Marys Primary School, including Thornhill, and Nos 17A and 17B, was founded in 1850/1 as a former British School. It is constructed of hammer dressed stone with a pitched slate roof and features paired ashlar stacks. The building has various coped gables on kneelers. The south block is one storey, while the north block is two storeys. There is a porch with an open bell-cote on the gable. The main door is part-glazed and has a fanlight set in a 4-centred arch with a hoodmould. The windows are mullion and transom style, also with hoodmoulds. The north block features planked double doors with elaborate hinges in a similar frame, flanked by lancet windows with hoodmoulds and triple stepped lancets with a hoodmould above. Nos 17A and 17B have planked doors set in single chamfered arches.