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.
Jiangchuan District, which belongs to Yuxi City, Yunnan Province, is located in the east of the central part of the province, between longitude 102 °35 "102 °55" east and latitude 24 °12 "24 °32 'north, bordering Huanning and Tonghai counties in the southeast, Hongta District in the southwest, Jinning District and Chengjiang District in the northwest, and District Street 1730 meters above sea level. The maximum horizontal distance from east to west is 31.9 km, and the maximum vertical distance from north to south is 35.7 km, with a total area of 850 square kilometers. Jurisdiction over 1 street, 4 towns and 2 townships. At the end of 2014, Jiangchuan's GDP reached 6.12796 billion yuan, an increase of 9.8 percent; the total financial revenue was 860 million yuan, of which local revenue was 596 million yuan; the disposable income of town residents was 26194 yuan, and the per capita net income of farmers was 9274 yuan. 2014