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.
Liaoning Province, referred to as "Liao", is the provincial administrative region of the people's Republic of China and the capital of Shenyang. Liaoning Province is located in the south of Northeast China, bounded by 38 °43 & # 39 N, 118 °53 & # 39 E, 118 °53 & # 39 E, bordering the Yellow Sea and Bohai Sea in the south, Hebei in the southwest, Inner Mongolia in the northwest, Jilin in the northeast, and North Korea across the river by the Yalu River in the southeast, covering a total area of 148600 square kilometers. The topography of Liaoning Province is roughly from north to south, tilting from the east and west sides to the middle, the mountains and hills are separated from the east and west, descend to the central plain, and incline to the Bohai Sea in the shape of a horseshoe, which is composed of mountains, hills and plains; across the Liao River, Hun River, Daling River, Taizi River, Laoyang River and Yalu River