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.
Jingtai County, which belongs to Baiyin City, Gansu Province, is located in the middle of Gansu Province, at the eastern end of Hexi Corridor, at the junction of Gansu, Ningxia and Mongolia provinces (regions), between 36 °43'N and 37 °38 °N and 103 °33'to 104 °43'E, with a total area of 5483 square kilometers. Jingtai County has a temperate arid continental climate. The name of the county implies the meaning of "prosperity, prosperity of the country and peace of the people". As of 2018, Jingtai County has jurisdiction over 8 towns and 3 townships, and the county government is stationed in a mountain town with a total population of 240000. The Western Han Dynasty buys Jiuyin and Guanwei County, which belongs to Wuwei County. The Qing Dynasty belongs to Gaolan and Jingyuan County of Lanzhou. Qing Dynasty Qianlong 22 years (1757) in this Hongshui Township Hongshui Hongshui County, is Gaolan County. In 1913, it was changed to Hongshui County. In the Republic of China