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.
Bagongshan District, which belongs to Huainan City, Anhui Province, is located in the west of Huainan City and the south bank of the Huaihe River. The total area is 105 square kilometers. In 2011, the total population was 180000. The district has jurisdiction over 3 streets and 2 towns: Xinzhuangzi Street, Tubazi Street, Bijiagang Street, Bagongshan Town and Shanwang Town. There are 25 communities and 21 village committees. The district government is stationed in Xinzhuangzi street. Huainan Railway Shuizhang Line and Huai (South) Li (Xin) Highway run through the region. The specialty is Bagongshan tofu. Places of interest include Bagongshan National Geopark, Bagongshan National Forest Park, Bagongshan National AAAA tourist area, Xiyunquan, Yuluquan, Lanxiangquan, Bagongxian Pavilion, Sunjia Garden, Nantang, Stone Forest, Yushan, Shimentan and so on.