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.
Shunqing District, Nanchong City, Sichuan Province, is located in the northeast of Sichuan Province, Zishunqingfu in the Southern Song Dynasty, Nanchong prefecture was changed to the city in 1993, and the county-level district was set up as Shunqing District in 2018. Shunqing District covers an area of 555.5 square kilometers, of which the built area of Shizhong District is 73 square kilometers. Shunqing District has jurisdiction over 7 townships and 12 urban subdistrict offices, with a total household registration population of 640000 and a permanent resident population of 855000. Shunqing District is located in the hilly area of northeastern Sichuan, with a subtropical humid climate, four distinct seasons, mild climate and abundant rainfall, passing through the Jialing River, an inland river in China. Shunqing is a trade center in northeast Sichuan and an old industrial base in northeast Sichuan. There are two industrial parks in Huanhua and Mianxi, covering an area of 15 square kilometers. There are moving (moving) big (forest) line modern agricultural park, moving green.