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.
Wangyi District District, located in the middle of Tongchuan City, Shaanxi Province, is not only the original political, economic, financial, cultural and commercial center of Tongchuan City, but also an important part of the northern urban area of Tongchuan (old city). Wangyi District has jurisdiction over Hongqi Street, Taoyuan, Qiyi Road, Youth Road, Wangjiahe, Wangyi six subdistrict offices and Huangbao Town, with a resident population of 198000 (2015) and a total area of 162.2 square kilometers. In 2013, the region achieved a total output value of 7.317 billion yuan, with Yaozhou Kiln Museum, Tankegou site, Qianfeng site, Xingyuan Temple Pagoda and other scenic spots or sites. On February 2, 2019, it was rated as a county-level national advanced unit of traditional Chinese medicine by the State Administration of traditional Chinese Medicine. November 2019