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.
Yujiang District, which belongs to Yingtan City, Jiangxi Province, is located in the northeast of Jiangxi Province and the middle and lower reaches of Xinjiang River, bordering Yingtan and Guixi City in the east, Jinxi County in the south, Dongxiang District in the west, and Wannian County and Yugan County in the north. Under the jurisdiction of 7 towns, 5 townships, 7 agricultural reclamation farms, a total of 6 communities, 116 administrative villages, 1 management committee. The total area is 936 square kilometers and the population is 380000 (2013). In 2016, Yujiang District completed a GDP of 11.3 billion yuan. Yujiang District is the "hometown of Chinese GE", "the hometown of Chinese sculpture", the national grain county and the lean pig production and export base county. In March 2019, it was listed as the first batch of revolutionary cultural relics protection and utilization district and county list.