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.
Jiangcheng Hani and Yi Autonomous County (Jiangcheng County for short) is a county under the jurisdiction of Pu'er City, Yunnan Province. Because Li Xianjiang, Manlaojiang and Mengye River surround the three rivers, they are called Jiangcheng. Jiangcheng County is located in the south of Yunnan Province, bordering Vietnam and Laos. The border is 183 kilometers long. It is the only county seat in Yunnan Province bordering Laos and Vietnam. In 2016, Jiangcheng County achieved a regional GDP of 2.67032 billion yuan, an increase of 9.0%, the added value of the primary industry was 897.05 million yuan, the added value of the secondary industry was 954.68 million yuan, the added value of the tertiary industry was 818.59 million yuan, and the tertiary industrial structure was 33.6%. Jiangcheng County's famous and special products are mainly Jiangcheng fragrant soft rice, roasted beef dry ba, Jiangcheng large yellow croaker, etc.; scenic spots are mainly ten-story Dashan, Menglie Lake Wetland Park