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.
Danzhou City is a prefecture-level city in Hainan Province. Danzhou City is located in the northwest of Hainan, bordering on the Beibu Gulf, 130km north to Haikou, the provincial capital, and 280km south to Sanya City; it has jurisdiction over 16 towns, a total of 275village committees and 1431 natural villages; the land area is 3400 square kilometers, accounting for 1x10 of the province; the total registered population is 945400 (2016); and the coastline is 267km long. Danzhou City is the economic, transportation, communication and cultural center of western Hainan. Hainan Yangpu Economic Development Zone, Chinese Academy of Tropical Agricultural Sciences and Danzhou Campus of Hainan University (formerly South China Tropical Agricultural University) are all in its territory. Danzhou City has successively won the "National Agricultural Top 100 City", "National Sanitary City", "National Civilization demonstration City", "National Garden City" and "National Garden City".