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.
Chongzuo, a prefecture-level city under the jurisdiction of Guangxi Zhuang Autonomous region, is located in the southwest of Guangxi Zhuang Autonomous region, with geographical coordinates between 21 °36` ~ 23 °22` N and 106 °33` ~ 108 °6` E. it is bordered by Nanning City and Fangchenggang City in the east and southeast, Baise City in the north and Vietnam in the west. It is the prefecture-level city with the longest land border in Guangxi, with a total area of 17440 square kilometers. Chongzuo is the most convenient land passage from China to ASEAN, an important node city of China-Vietnam Corridor and Nanning-Singapore Economic Corridor, and one of the cities of Guangxi Beibu Gulf Economic Zone. There are 3 national first-class ports, 4 second-class ports and 13 border exchange points, which is the city with the largest number of border ports in China. The topography of Chongzuo City is slightly higher in the northwest and southwest.