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Cobblestone is a natural building material based on cobble-sized stones , and is used for pavement roads, streets, and buildings . In England , it was commonplace since ancient times for flat stones with a flat narrow edge to be set on edge to provide an even paved surface. This was known as a 'pitched' surface and was common all over Britain, as it did not require rounded pebbles. Pitched surfaces predate the use of regularly-sized granite setts by more than a thousand years. Such pitched paving is quite distinct from that formed from rounded stones , although both forms are commonly referred to as 'cobbled' surfaces. Most surviving genuinely old 'cobbled' areas are in reality pitched surfaces. A cobbled area is known as a "causey", "cassay" or " cassie " in Scots (probably from causeway). Setts are often idiomatically referred to as "cobbles", although a sett is distinct from a cobblestone by being quarried or shaped to a regular form, whereas cobblestone is generally of a naturally occurring form.