The Folkton Drums are decorated solid chalk 'drums' form the neolithic period, The first example was found in 1889 in the northern UK, and since then others have been unearthed in the south. All are now in the British Museum. ( ref. with photos )
The 5,000 year-old 'drums' are around 140cm in diameter, and, despite their name, are not thought to have had any musical use (being solid chalk). They seem to be largely un-worn, suggesting they were well looked after, or little used.
It's not known what function they may have had. One theory, from the University of Manchester and UCL Institute of Archaeology suggests they may have been measuring devices ( ref.)