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.
Yushui District, Xinyu City District, Jiangxi Province, where the CPC Xinyu Municipal Committee and Municipal Government are located, is the city's political, economic, commercial, cultural, scientific and educational, and transportation center. Located in the west-central part of Jiangxi Province, east of Xinyu City, the middle and lower reaches of the Yuan River. Camphor trees and Xingan in the east, Xiajiang and Ji'an in the south, Fenyi in the west, Shanggao and Gao'an in the north, 160 kilometers away from the provincial capital Nanchang. It has jurisdiction over 10 towns, 6 townships and 5 subdistrict offices. The total area is 1775 square kilometers and the total population is 801000 (2008). Among them, the non-agricultural population is 303000. Yushui District is a subtropical humid climate with four distinct seasons, mild climate, sufficient sunshine, abundant rainfall, long frost-free period, extremely short winter, fertile land and nearly 50% forest coverage. In March 2019, it was selected into the first batch of revolutionary cultural relics protection and utilization areas.