A mesa is an isolated, flat-topped elevation, ridge or hill, which is bounded from all sides by steep escarpments and stands distinctly above a surrounding plain. Mesas characteristically consist of flat-lying soft sedimentary rocks capped by a more resistant layer or layers of harder rock, e.g. shales overlain by sandstones. The resistant layer acts as a caprock that forms the flat summit of a mesa. The caprock can consist of either sedimentary rocks such as sandstone and limestone; dissected lava flows; or a deeply eroded duricrust. Unlike plateau, whose usage does not imply horizontal layers of bedrock, e.g. Tibetan Plateau, the term mesa applies exclusively to the landforms built of flat-lying strata. Instead, flat-topped plateaus are specifically known as tablelands.
Chaonan (Chaonan), Shantou City, Guangdong Province. In 2003, Zhi District belongs to Chaozhou in successive dynasties, which gets its name because of its geographical location in the south of Chaoyang City (county level). The word "Chaonan" is the abbreviation of "Chaoyang South". Chaonan District is located in the southwest of Shantou City, bordering the South China Sea to the east, Puning to the west, Huilai to the south and Chaoyang District to the north. Chaonan District has a total area of 596.42 square kilometers, accounting for 30% of the total area of Shantou City, with a total population of 1.29 million (2010), accounting for 24% of the total population of Shantou City. Chaonan region has a coastline of 14.7km, a sea area of more than 4000 square kilometers, a mountain area of 382300 mu and an arable land area of 208200 mu. The urban area is away from the central city of Shantou