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.
Qinghe District, which is under the jurisdiction of Huaian City, Jiangsu Province, is the resident of the municipal party committee and municipal government of Huaian City, and is the political, transportation, economic and cultural center of Huaian City and an important window for foreign exchanges. Qinghe District has jurisdiction over 7 streets and 40 community committees in Huaihai Street, Changdong Street, Changxi Street, Fuqian Street, Liu Shu Wan Street, Shuidukou Street, Egret Lake Street. Qinghe District is located in the main urban area of Huaian City. It borders Huai'an District in the east, Qingpu District and Huaiyin District in the west, Qingpu District in the south and Huaiyin District in the north, with a total area of 32.28 square kilometers (2013) and a resident population of 242700 (2013). In 2013, Qinghe District achieved a GDP of 12.298 billion yuan and a total investment of 10.602 billion yuan in fixed assets.