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.
Lean is located in the hinterland of central Jiangxi Province, southwest of Fuzhou City. It is originally Lean Township of Chongren County and Songzhi County, named after Lean Township. It is bordered by Chongren County and Yichuang County in the east, Ningdu in Ganzhou City in the southeast, Yongfeng in Ji'an City in the southwest, Xingan in the northwest and Fengcheng in Yichun City in the north. Fuji Expressway and Changning Expressway pass through the hinterland of our county and are connected with Jiangxi, Guangdong and Jingfu Expressway, which greatly shortens the distance between the Pearl River Delta, the Yangtze River Delta and the Southeast Fujian Delta. The county covers a total area of 2412.59 square kilometers, with 9 towns and 7 townships, with 175 village committees and 1651 village groups, with a total population of 365000, including 287000 agricultural people. In July 2019, he won the title of "China Natural oxygen Bar" in 2019.