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.
Taishan City, formerly known as Xinning, was established in 1992 as a county-level city in Jiangmen City, Guangdong Province, located in the southwest of the Pearl River Delta, adjacent to Hong Kong and Macao and the South China Sea, adjacent to Xinhui, Kaiping, Enping and Yangjiang respectively. It has the reputation of "the first hometown of overseas Chinese", "two Taishan inside and outside", "the hometown of volleyball", "the hometown of Guangdong Music", "the hometown of Chinese Quyi" and "the hometown of elegant Art". Taishan covers an area of 3286 square kilometers. It now has jurisdiction over two experimental areas, 20 towns and an overseas Chinese farm, which is divided into 503 village committees and 3655 natural villages. At the end of 2016, the city's total registered public security population was 970500, including 395200 in urban areas and 575300 in rural areas. In November 2018, it was identified as the leader by the Ministry of Science and Technology.