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.
Mingshan District, which belongs to Benxi City, Liaoning Province, is located in the northeast of Benxi City, with an area of 408.1 square kilometers. The district has jurisdiction over 1 town and 8 streets, 25 administrative villages and 50 community neighborhood committees, with a resident population of 400000 (2014). Mingshan District is bordered by Pingshan District in the southwest, Xihu District in the northwest, Nanfen District in the south and Benxi Manchu Autonomous County in the east. It is 62 kilometers away from the provincial capital Shenyang, 150 kilometers away from Yingkou, 320 kilometers away from Dalian, 640 kilometers away from the capital Beijing and 610 kilometers away from Tianjin. In 2013, the regional GDP reached 16.57 billion yuan, an increase of 11.3% over 2012.