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.
Gaozhou, county-level cities under the jurisdiction of Guangdong Province, important small and medium-sized cities of Beibu Gulf Urban agglomeration in China, economically strong counties (cities) in mountainous areas of Guangdong Province, educational counties (cities) of Guangdong Province, and county medical centers of Guangdong Province, the comprehensive strength of economic and social development has long been in the forefront of Guangdong counties. Gaozhou is located in the southwest of Guangdong Province, southwest of Guangdong, near the South China Sea in the east, Jianjiang Plain in the south, Guangxi in the west, Yunkai Mountain in the north, six counties and cities in Guangdong and Guangxi in the west, Yangchun City and Dianbai District in the east, Maonan District in the south and Xinyi City in the north, bordering Huazhou City in the southwest and Beiliu City in Guangxi in the northwest. Gaozhou, formerly known as Maoming County and Gaozhou County, evolved from the administration of Maoming County by Gaozhou Prefecture (Road) in the Yuan Dynasty, while the place name of "Gaozhou" evolved from "Gaoliang". Before the Sui Dynasty, Gaoliang County was in the area of Enping and Yangjiang; since the Sui and Tang dynasties