The local historical pronunciation of the village is 'Stew-key'. This is primarily due to the underlying glauconitic clays (blue-green clays – formerly Blue Marl), BGS lexicon lithological description: Pale to dark grey or blue-grey clay or mudstone, glauconitic in part, with a sandy base. Discrete bands of phosphatic nodules (commonly preserving fossils), some pyrite and calcareous nodules. In Norfolk, the Cretaceous Gault Formation becomes calcareous before passing northwards into the Hunstanton Formation ("Red Chalk"). In places thin, variable junction beds at the base include some limestones. (BGS lexicon: Gault Formation which belongs to the Selbourne Group).