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.
Shanyang District belongs to Jiaozuo City, Henan Province, bordering Shanxi by Taihang Mountain in the north, the Yellow River in the south, and Zhengzhou and Luoyang across the river. it is the economic, cultural, financial and commercial center of Jiaozuo City. Shanyang District, with a total area of 74.4 square kilometers, has jurisdiction over 10 streets, 19 administrative villages and 31 communities, with a total population of 249733 (2012). China's key cultural relics protection units-after thousands of years of Han Xiandi relegated Shanyang Old City, famous at home and abroad, Yao Wang Temple, and shrine, and so on. Shanyang District within the jurisdiction of the south-to-north water transfer, west-to-east gas transmission through the city. The GDP of Shanyang District in 2012 is 2.321 billion yuan. In 2009, Shanyang District won the civilized urban area of Henan Province, the advanced cultural area of Henan Province, the advanced unit of cultural activities in the square of "Happy Central Plains Wushanyang", and the city's "New Fashion".