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.
Anhua County is located in the middle of Zishui, north of central Hunan, north of Xuefeng Mountain, bordered by Taojiang and Ningxiang in the east, Lianyuan and Xinhua in the south, Xupu and Yuanling in the west, Changde and Taoyuan in the north. The main belt of the northern section of Xuefeng Mountain, called Meishan in Anhua in ancient times, is the birthplace of Meishan culture. Zong Xining, the god of the Song Dynasty, bought the county in 1072. With a total area of 4950 square kilometers, Anhua is the third largest county in Hunan Province, with a mountain area of 82%. It is also a typical mountain county and reservoir county, with a woodland area of 5.36 million mu and a forest coverage rate of 76.51%. In 2013, Anhua had jurisdiction over 5 townships and 18 towns with a total population of 1.03 million. Anhua is a famous county of non-ferrous metals, hydropower resources, forestry resources, tea production and medicine industry in Hunan.