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.
Ganluo County, which belongs to Liangshan Yi Autonomous Prefecture of Sichuan Province, is located in the southwest of Sichuan Province and in the north of Liangshan Yi Autonomous Prefecture, across longitude 102 °27038 "~ 103 °011545" east and latitude 28 °38 "24" ~ 29 °1832 "north. It is bounded by Maanshan in the east, Ebian County and Jinkou River in Leshan City in the east, Meigu County and Yuexi County in the south, Shimian County in Ya'an City in the west, and Dadu River and Ya'an City in the north. The administrative area of the county covers an area of 2150.79 square kilometers, with a total of 190000 people by 2012. When the county was founded in December 1956, it was called Ganluo County. Because the pronunciation error between the word "Ga" and the original place name was too big, it was renamed Ganluo County in 1959 with the approval of the State Council. In September 2016, the State Council approved the addition of Ganluo County to the country.