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.
Longde County, which belongs to Guyuan City, Ningxia Hui Autonomous region, is located at the western foot of Liupan Mountain and the southern border of Ningxia. It lives in the capital cities of Yinchuan, Xi'an and Lanzhou. 312 National Highway runs through the east and west, and Qinglan Expressway passes through the border. Between latitude 35 °21-#39;-35 °47-#39; and longitude 105 °48-#39;-106 °15-#39;. East Guanshan, west overlooking Hetao, south Qinzhou, north Ningshuo; lapel belt Qinliang, support Xifu, known as "Guanlong lock key". It is 47 kilometers from north to south and 41 kilometers from east to west, and the county covers an area of 985 square kilometers. As of 2018, it has jurisdiction over 10 townships and 3 towns with a total population of 175392. The county government is stationed in Chengguan Town. As of 2