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.
Xinhui (Xinhui), known as Gangzhou in ancient times, is now under the jurisdiction of Jiangmen City, Guangdong Province, located on the banks of Yinzhou Lake and the lower reaches of the Tanjiang River in the southwest of the Pearl River Delta, adjacent to Zhongshan in the east and Doumen in the south, Jiangmen and Heshan in the north, Kaiping and Taishan in the west, and Taishan in the southwest. According to the key points of the Pearl River Delta, it borders on the South China Sea, adjacent to Hong Kong and Macao, with a land area of 1355 square kilometers and a household population of 760000. Xinhui, located south of the Tropic of Cancer, has a subtropical maritime climate, with an average temperature of 23.8 ℃ and rainfall of 1893.1 mm in 2015. Mild climate, fertile land, dense river network, rich products, Xinhui sunflower art is famous, Xinhui tangerine peel is famous all over the country. It is known as "sunflower village", "hometown of tangerine peel" and "land of fish and rice". Xinhui is a famous historical and cultural city in southern Guangdong.