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.
Guangchang County, Xiazhong County, Fuzhou City, Jiangxi Province, is located in the south of Fuzhou City, at the western foot of Wuyi Mountain. It is bordered by Jianning County in Fujian Province in the east, Shicheng County in the south, Ningdu County in the west and Nanfeng County in the north. The county is 45 kilometers wide from east to west, 55 kilometers from north to south, with a total area of 1612 square kilometers. It has jurisdiction over 6 towns, 5 townships, 1 field, 129 administrative villages and 1 provincial industrial park, with a total population of 250000. Guangchang County is the south gate of Fuzhou City and the birthplace of Fuhe River, the second largest river in Jiangxi. The county was founded in the eighth year of Shaoxing in the Southern Song Dynasty (1138). It got its name because of "Road to Fujian and Guangzhou, and the county belongs to Jianchang". Because it is rich in white lotus, it is known as "the hometown of white lotus in China". In 2016, the county's GDP reached 5.763 billion yuan, an increase of 8.7% over the same period last year. On February 23, 2018, Jiangxi Province withdrew from Guangchang County.