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.
Xinyi, known in ancient times as Liangde County, Huaide County, Nanfuzhou and Dou Zhou. The county-level city hosted by Maoming City, Guangdong Province is located in the southwest of Guangdong Province and the north of Maoming City. It is bordered by Yangchun in the east, Gaozhou in the south, Beiliu and Rong County in Guangxi in the west, and Luoding City and Cenxi City in Guangxi in the north. Xinyi is rich in resources and is one of the largest production bases of bamboo, jade, rosin and granite plates in the province, as well as an important production base of mountain pheasant, Sanhua plum, litchi, longan, southern medicine and out-of-season vegetables. Known as "the jade capital of the south", "the hometown of bamboo weaving", "the hometown of hydropower", "the hometown of Sanhua and Li", "the hometown of southern medicine", "mountain chicken kingdom" and other laudatory names. Xinyi has beautiful scenery, and the developed tourist attractions include Xijiang Hot Spring, Tianma Mountain, Shigen Mountain, Daren Mountain, Taihua Mountain, Jiamen Gorge rafting and so on.