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.
Baita District, Liaoyang City, Liaoning Province, Baita District is located in the middle of Liaoyang City, east of Changda Railway and west of Taizi River. As of 2013, Baita District has a total area of 50.95 square kilometers, a population of 402100, 11 streets, a total of 60 communities and 6 villages. In 2012, the GDP of Baita District reached 17 billion yuan, the public budget revenue reached 1.25 billion yuan, the investment in fixed assets of the whole society reached 11.9 billion yuan, the total retail sales of consumer goods reached 11.6 billion yuan, and the added value of the service industry reached 13.6 billion yuan. Baita District gets its name because of the national key protected cultural relics, the Baita of the Liao Dynasty. Cao Xueqin's former residence is also in Baita District. Baita District is "advanced area of civilized city construction", "demonstration area of universal education" and "national harmonious community construction".