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.
Xiantao City is a county-level city directly under the jurisdiction of Hubei Province. Xiantao City is an important member of Wuhan urban agglomeration and the middle reaches of the Yangtze River, and the hometown of Asian gymnastics. Xiantao, with a history of more than 1500 years, is one of the birthplaces of Jing-Chu culture. Xiantao depends on the Han River in the north, the Yangtze River in the south and Wuhan in the east. 318 National Highway, Han-Yi High-speed Railway and Shanghai-Chongqing Expressway run from east to west, and Suiyue Expressway and Wuhan City Ring Road (Wuhan sixth Ring Line) run longitudinally through the north and south. Xiantao south to Guangzhou, north to Beijing, east to Shanghai, west to Chengdu and other megacities are all within a radius of 1000 kilometers. As of 2016, Xiantao City has a total area of 2538 square kilometers and has jurisdiction over 3 streets, 15 towns and 7 township units with a registered population of 1.5635 million. Xiantao is a national garden city.