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.
Ziyun Miao Buyi Autonomous County is located in the southwest of Guizhou Province and under the jurisdiction of Anshun City. It is located at 105 °55 & #39;-106 °29 & #39;, 25 °21 & #39;-26 °3 & #39;. The county is bordered by Changshun and Luodian counties to the east, Wangmo County to the south, Zhenning County to the northwest and Xixiu District to the north. The county has jurisdiction over 2 streets, 8 towns and 2 townships, 161 kilometers from the provincial capital Guiyang, 76 kilometers from north to south and 52 kilometers from east to west. The total area is 2284 square kilometers. The total population is 373130 (2013 registered population). The government is stationed in Songshan Town. In 2013, Ziyun Miao Buyi Autonomous County achieved a gross domestic product (GDP) of 352499.