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.
Renqiu City is a county-level city under the jurisdiction of Cangzhou City, Hebei Province, located in the middle of Hebei Province, west of Baiyangdian, is the hometown of doctor Bian Que, Huabei Oilfield headquarters is located. The city covers an area of 1012 square kilometers and has jurisdiction over 7 streets, 9 towns, 6 townships, 2 development zones (industrial parks) and 413 administrative villages. The total population is 867148 (2013). Renqiu is located in the north-central part of the North China Plain, mainly growing wheat, corn and other food crops. Rich in underground oil and natural gas resources, it is an important oil producing area and petrochemical base in North China. Renqiu is one of the major cities and cities designated by the State Council to open to the outside world and the economic circle around Beijing and Tianjin. Since the Ninth five-year Plan, Renqiu's comprehensive strength has been in the forefront of the "top 10" counties and cities in Hebei Province, and has been listed among the top 100 counties and cities in the country for many years in a row.