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.
Gong County is a county under the jurisdiction of Yibin City, Sichuan Province. It is located in the south of Yibin City, between longitude 104 °38mm muri 105 °02' and latitude 27 °53mm Mel 28 °31', north is bounded by Gaoxian County, 46 km away from Cuiping District, Yibin City, south by Daxueshan, 69 km away from the county seat of Weixin County, Yunnan Province, west by Yunlian County, southeast and northeast by Xingwen County and Changning County. The county government is stationed in the town, 56 kilometers away from the municipal government. There are trunk highways such as Xugao Highway, Chuanyun Highway and Yiwei Highway connecting Yunnan, Guizhou and Sichuan provinces in Gongxian County. Chengyi Railway and Jinyun Railway run through the county, which is an important transportation hub and material distribution center in the south of Yibin City. The high-grade cement road goes directly to the urban area of Yibin City and can reach Yibin Airport and Yangtze River Shipping Terminal within 1 hour. Gong County is important in Sichuan Province.