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.
Fu'an City (ancient Fu'an County, Funing County) belongs to Ningde City, which is located in the northeast of Fujian Province. It is located in the southeast slope of Jiufeng Mountains, the southwest of Taimai Mountains and the southeast extension of Donggong Mountains, and the geographical location is between 26 °41 °N and 27 °24'N and 119 °52'E longitude. The administrative area is 1880.1 square kilometers. It is bordered by Zherong County in the east, Zhouning County in the west, Shouning County in the north and Ningde City in the south. Fu'an City has a warm and humid climate, which belongs to the mid-subtropical marine monsoon climate. The average annual temperature is 13.6 ℃ ~ 19.8 ℃, the annual rainfall is 1350 ~ 2050mm, and the average frost-free period is 287days. The resident population is 574500 (at the end of 2016), with 13 towns, 5 townships and 4 streets, and 2 provinces.