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.
Daxin County is a border county in Guangxi, China, and it is also a county under the jurisdiction of Chongzuo City, Guangxi Zhuang Autonomous region. Daxin County is located in the southwest of Guangxi, between latitude 22 °29 / 23 °05 'north and longitude 106 °39 / 107 °29' east, Longan County in the northeast, Tiandeng County in the north, Jingxi City in the northwest, Longzhou County in the southwest, and the Democratic Republic of Vietnam in the west. the national boundary is more than 40 kilometers long, and the county people's government is 143 kilometers away from Nanning, the capital of the autonomous region. Daxin County has a long history. Human beings lived here more than 4500 years ago in the early Neolithic Age. Daxin is an area where the chieftain has ruled for a long time and has a relatively complete system. On January 25, 2019, he was selected as the national "Ping an Agricultural Machinery" demonstration county in 2018. March 2019, ranked the first