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.
Xigaze City in Tibet Autonomous region has jurisdiction over counties, including Sima Town, Pari Town, Shangyadong Township, Xiayadong Township, Kangbu Township, DUI Na Township and Jiru Township. It is located in the southeast of Xigaze City, Tibet Autonomous region, bordering Kangma County, Bailang County and Gangba County to the north, and extending wedge-shaped to the south between neighboring India and Bhutan. It is one of the border counties of the Tibet Autonomous region. Located in the middle of the Himalayas (north in the north, south in the south), the central part is the Zhuomulari Snow Mountain in the town of Pari, the terrain is low in the north, high in the middle and low in the south. The county has a total area of 4240 square kilometers, including 12000 mu of arable land and 240000 mu of forest, with an average elevation of 3400 meters above sea level. The people's Government of Yadong County was formally established in June 1960, and the county has jurisdiction over DUI Na Township, Jiru Township, Pari Town and Kangbu Township.