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.
Dawa District belongs to Panjin City, Liaoning Province, which is located in the southwest of Liaoning Province. The lower reaches of the Daliao River and Shuangtaizi River (Liao River) enter the sea and the northeast bank of Liaodong Bay. The central location is 122 °07 north latitude and 40 °98 'east longitude, facing Haicheng and Dashiqiao in the southeast. As of 2014, Dawa District (then known as Dawa County, the same below) covers an area of 1387 square kilometers, has jurisdiction over 15 towns, with a registered population of 350000 and a resident population of 430000. In Dawa District, there are General Zhang Xueliang's hometown, Ganggang Scenic spot, Liaohe Delta Wetland and other scenic spots, as well as historical celebrities such as Zhang Xueliang, Hu Jinbo, Li Rongjing and so on. At the end of 2018, the GDP of Dawa region reached 13.75 billion yuan, the general public budget revenue reached 1.22 billion yuan, and the added value of industries above scale reached 17.6%.