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.
Wenchang, known as Zibei in ancient times, has a history of more than 2100 years since the Western Han Dynasty. It is one of the three historical ancient cities in Hainan. It is a famous hometown of overseas Chinese in China and one of the important base areas of the Qiongya Revolution. The birthplace of Minnan culture in Hainan, the location of Hainan Wenchang Space launch Center, is the fourth space city in China. It is located in the integrated economic circle of "one hour Economic Circle" and "Haicheng text" in Qiongbei Comprehensive Economic Zone. Qiongbei is one of the important regional centers of economy, culture, transportation, science and technology and tourism. Wenchang, Haikou and Sanya have been selected as "charming cities with Chinese characteristics" by global organizations. they are national demonstration cities for scientific and technological progress, national advanced cities for scientific and technological progress, and advanced cities for national culture. The city with 278.5 kilometers of coastline is the longest in Hainan, and Qinglan Port in the city is open to the outside world at the national level.