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.
Heshan City, a county-level city under the jurisdiction of Guangxi Zhuang Autonomous region, is a new industrial and mining city hosted by Laibin City, which is located in the west, southeast and west of Laibin City and connected with Xingbin District. Heshan has convenient transportation, National Highway 322 Nanliu Secondary Highway runs through the north and south of the city, more than 50 kilometers east of Nanliu Expressway; the railway is connected with the Hunan-Guangxi railway trunk line; shipping can reach Guigang, Wuzhou, Guangzhou and Hong Kong and Macao. Heshan City was awarded the title of "Top Ten counties (cities) in Guangxi Economic Development" in 2003 and 2005, and entered the list of "100 counties and cities with the fastest improvement in the basic competitiveness of China's county economy" in 2004. In March 2009, Heshan was listed as one of the second batch of 32 resource-exhausted cities by the State Council. After the transformation, it has received strong support from government funds and projects at all levels.