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.
Tianzhu County, located in the east of Guizhou Province, is under the jurisdiction of Qiandongnan Miao and Dong Autonomous Prefecture. Tianzhu County is located in eastern Guizhou and the lower reaches of Qingshui River, bordering Xinzhuang County, Jingzhou County, Huitong County, Zhijiang County and Jianhe County, Jinping County and Sansui County of Guizhou Province. In 2013, Tianzhu County achieved a GDP of 4.91 billion yuan, financial revenue of 654 million yuan, investment in fixed assets of 7.098 billion yuan, per capita disposable income of urban residents 19035 yuan, and per capita net income of farmers 5601 yuan. Tianzhu County specialties are: Tianzhu navel orange, Tianzhu local duck and so on. Famous figures are: Wang Tianpei, Yang Changhuai and so on. September 25, 2018, won the honor of "2018 e-commerce into the rural comprehensive demonstration county" of the Ministry of Commerce.