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.
Lishu County, which belongs to Siping City, Jilin Province, is located in the southwest of Jilin Province, located in the hinterland of Songliao Plain, bounded by Liaohe River to the east of Gongzhuling City in the east, Shuangliao City in the north, Changtu County in Liaoning Province in the west and Siping City in the south. It is between 123 °45 degrees east longitude 124 °53 kilometers east longitude and 43 °02 degrees north latitude, 43 °46 degrees north latitude. The total area is 4209 square kilometers. The terrain is high in the southeast and low in the northwest. Low mountains and hills in the south, wavy plains in the middle, and East Liaohe alluvial plain in the north. Lishu established a county in the fourth year of Guang Xu of the Qing Dynasty (1878), formerly known as "Fenghua County". It was once the birthplace of the Qing Emperor Nuerhachi "Fujin", the birthplace of Empress Dowager Xiaocigao, the birth mother of Empress Taiji and the ancestral place of the Empress Dowager Cixi. Lishu County has the reputation of "Northeast granary" and "Songliao Pearl". As of 201