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.
Maonan District is under the jurisdiction of Maoming City, Guangdong Province, which is located in the western part of Guangdong Province in the southwest of Guangdong Province. It is named because it is located in the south of Maoming County (now the main body belongs to Gaozhou City and Maonan District). It is located between 110 °44 east longitude, 110 °58 'east longitude and 21 °32-21 °49' north latitude, with Dianbai to the east, Wuchuan to the south, Huazhou to the west and Gaozhou to the north. The area has jurisdiction over 8 streets and 9 towns (Yangjiao Town is divided into Yangjiao Town in September 2017, with additional Chengnan streets), 133 village committees and 85 neighborhood committees (excluding Yangjiao Town), with a total area of 526 square kilometers (excluding Yangjiao Town). By the end of 2011, Maonan District had 33 ethnic groups and a population of more than 8,000 ethnic minorities. (note: unless otherwise stated, the population, area and other statistics of this entry