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.
Ximeng WA Autonomous County is located in Pu'er City, Yunnan Province. It is located in the southwest of Yunnan Province and the AWA Mountain area in the west of Simao City. It spans 99 °18'to 99 °43 'east longitude and 22 °25' to 22 °57 'north latitude. It borders Lancang County in the east, northeast and southeast, Menglian County in the south, and Menglian County in the south. The border line is 89.33 km long. The county seat is 864 km away from the provincial capital Kunming and 293 km away from Simao. The territory has a horizontal distance of 40 kilometers from east to west and 60 kilometers from north to south, with a total area of 1353.57 square kilometers. At the end of 2016, the total population of Ximeng WA Autonomous County was 94721, of which WA accounted for 71.6%. It has jurisdiction over 5 towns and 2 townships, and the county people's government is stationed at No. 1 Mengka Road, Mengsuo Town. Western League