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.
Xiejiaji District, which belongs to Huainan City, Anhui Province, is located in the west of Huainan City, between the Huaihe River and the Dongfei River. It is located at 116 °54 miles east longitude 117 °01 'and 32 °32 degrees north latitude 32 °39'. Xiejiaji District was established in October 1960, bordering Changfeng County in the south, Shou County in the west, Huaihe River and Bagongshan in the north, and is the central city in the west of Huainan City. Xiejiaji District has jurisdiction over two provincial industrial parks, five streets, six towns and three townships. In 2015, Xiejiaji District achieved a GDP of 7.71 billion yuan. Xiejiaji District has the warring States Chunxiang Chunshenjun Huang Xie Tomb, the Qing Dynasty Mariner Yang Qizhen Tomb, Lai Shanji Mosque, the provincial scenic spot Wolongshan Forest Park and Wabu Lake.