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.
Yinjiang Tujia and Miao Autonomous County, Tongren City, Guizhou Province, is located in the northeast of Guizhou Province and the west of Tongren City, Guizhou Province, with high topography in the east and low in the west, tilting southeast to the northwest, no severe cold in winter and no hot summer in summer, with a total area of 1969 square kilometers. it has jurisdiction over 3 streets, 13 towns and 1 township with a total population of 454500 in 2018. Yinjiang, located at the western foot of Fanjing Mountain, began in Siwang County during the reign of Tang Wude (618-626). In 1987, it was approved by the State Council to establish Yinjiang Tujia and Miao Autonomous County, which passes through the city of 303, 304 Provincial Highway and Hangzhou-Rui Expressway. Yinjiang is inhabited by Tujia, Miao, Han and other ethnic groups. Mr. Yan Yinliang, who is famous for his inscription on the plaque "Summer Palace", is one of the representatives of his calligraphy culture. Gave birth to State Councilor Dai Bingguo and American space doctor Wu Xue.