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.
Zhijin County is located in the west of central Guizhou-the economic core area of central Guizhou. It is the lower county of Bijie City, Guizhou Province, Dafang County and Qianxi County of Bijie City to the north, Qingzhen City of Guiyang City and Pingba District of Anshun City to the east, Xixiu District of Anshun City to the southeast, Puding County of Anshun City to the south, Liuzhi Special Zone of Liupanshui City to the southwest, and Nayong County of Bijie City to the west. Zhijin County is located in the triangle zone of the confluence of the Liuchong River and Sancha River, a tributary of the Wujiang River. The county seat is 157km away from the provincial capital Guiyang and 144km from Bijie; the lowest elevation is 860m, the highest elevation is 2262 m, and the county seat elevation is 1310 m; the annual average temperature is 14.1 ℃, the annual rainfall is 1436 mm, the annual sunshine is 1172 hours, and the frost-free period is 327d, which belongs to subtropical monsoon climate. Zhijin County has jurisdiction over 6 streets, 16 towns, 3 townships and 7 ethnic groups.