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.
Ningjin County is under the jurisdiction of Xingtai City, Hebei Province, located in the south-central part of Hebei Province and the north of Xingtai City, with an administrative area of 1107 square kilometers, 1 street, 11 towns and 5 townships, with a resident population of 781400 (2014). 23 Tianbao East Street, Fenghuang Town, County people's Government. Ningjin County is located in the alluvial plain at the eastern foot of Taihang Mountain, with low, flat and open terrain, tilting from northwest to southeast. Fei River, Fuyang River, Laozhang River, Beili River, Huan River and other 11 rivers converge here, known as "the tip of the Nine Rivers". It belongs to the warm temperate zone with semi-arid monsoon climate. Mineral resources include oil, natural gas, rock salt, geothermal and so on. Ningjin County is a traditional agricultural county, growing crops mainly to wheat, corn, specializing in snow pear, Yali pear, edible fungi. The industry has formed solar cells with monocrystalline silicon,