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.
Gongshan Dulong Nu Autonomous County (Gongshan County) is an autonomous county under Nujiang Lisu Autonomous Prefecture, Yunnan Province. Located in the northern section of Nujiang Grand Canyon in northwestern Yunnan, it is located between longitude 98 °08mo 98 °56km east and latitude 27 °29km Latitude 28 °23'. It is connected with Deqin and Weixi counties in Yunnan Province in the east, Fugong County in Nujiang Prefecture in the south, Chayu County in the Tibet Autonomous region in the north and Myanmar Union in the west. The border is 172.08 kilometers long and covers an area of 4506 square kilometers. In 2007, Gongshan Dulong Nu Autonomous County achieved a gross national product of 235.2 million yuan. The main scenic spots of Gongshan Dulong Nu Autonomous County are Biluo Snow Mountain, Gaoligong Mountain, Dandanglika Mountain, Nujiang River, Dulong River and so on. On September 25, 2018, the Ministry of Commerce was awarded "2018"