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.
Anyue County, which belongs to Ziyang City, Sichuan Province, is located in the central part of Sichuan Basin, the east of Ziyang City, the center of Chengdu-Chongqing Economic Zone and the straight line midpoint of Chengdu and Chongqing, and is known as "the Heart of Chengdu and Chongqing". Between latitude 29 °40 °32 "~ 30 °18 °53". It is bordered by Tongnan District of Chongqing City in the east, Dazu District of Chongqing City in the southeast, Rongchang District of Chongqing City and Dongxing District of Neijiang City in the south, Dongxing District of Neijiang City in the southwest, Zizhong County of Neijiang City in the west, Lezhi County in the northwest and Anju District of Suining City in the northwest. In 2018, Anyue County covers an area of 2700 square kilometers and has jurisdiction over 69 townships with a total population of 1.63 million. The GDP of the whole county has reached 34.501 billion yuan, and the investment in fixed assets of the whole society has reached 14.556 billion yuan.