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.
Dingxi is a prefecture-level city under the jurisdiction of Gansu Province, located in central Gansu, commonly known as "Longzhong"; it is located in the confluence area of the Loess Plateau and West Qinling Mountains, with large ups and downs, vertical and horizontal mountains and different shapes; its climate type belongs to the south temperate zone semi-humid-mid-temperate zone semi-arid zone, the continental monsoon climate is obvious; the city's total area is 20330 square kilometers, under the jurisdiction of 1 district, 6 counties; 2018 resident population 2.8217 million. Dingxi is a national summer resort observation city, with more than 60 tourist attractions and tourist spots. Weiheyuan, Guiqing Mountain, Shade Mountain, Langdu Wetland grassland and Taohe tourist promenade are all places for summer leisure. Dingxi not only gave birth to Li culture, but also the intersection of prehistoric cultures such as Majiayao, Qijia, Siwa, Xindian and other prehistoric cultures and important calligraphy and painting in the country.