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.
Licheng District (Putian County, Xinghua Prefecture) is located in the middle of the southeast coast of Fujian, bordering Hanjiang District in the north, Liancheng District in the west and southwest, and Xinghua Bay in the east and north. It is one of the central urban areas and economic centers of Putian City. Licheng District is a new urban area established with the approval of the State Council in 2002. it has jurisdiction over 4 towns of West Tianwei Town, Huangshi, Xindu, Beigao and 2 streets of Zhenhai and Gongchen. There are 118 village committees and 12 neighborhood committees, with a total area of 269.66 square kilometers and a total population of 463800. Licheng District, referred to as Licheng, is a district under the jurisdiction of Putian City. At the same time, Licheng is another name for Putian in Fujian Province. Putian is named Licheng because it is rich in litchi. There is a national cultural relic protection unit Ninghai Bridge.