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.
Yingjisha, a Uyghur language, means "new town". In the Qing Dynasty, the Tu Zhi of the Western regions was made as Ingassar. It has been an important town between Yeerqiang and Kashgar since ancient times, and the military station was set up here in the Qing Dynasty. In the 24 year of Emperor Qianlong (1759), after suppressing the rebellion of Da, Xiao and Zhuomu, he was named Yingjishar. Yingjisha County, which belongs to Kashgar, Xinjiang, is located in the southwest of Xinjiang Uygur Autonomous region, at the northern foot of Kunlun Mountains and on the western edge of Tarim Basin; it is bordered by Shache County in the east, Aktao County in the southwest and northwest, and Shule and Yuepu Lake in the northeast; it is famous as "the hometown of Chinese knives", "the hometown of apricots in China" and "the hometown of Dawazi in China". It is the post station of the ancient land Silk Road and one of the eight major cities in southern Xinjiang. Yingjisha County has a total area of 3425 square kilometers, has jurisdiction over 2 towns and 12 townships, and has an arable land area of 380300.