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.
Fuchuan Yao Autonomous County, which belongs to Hezhou City, Guangxi Zhuang Autonomous region, is located in the northeast of Guangxi, between Dupang and Mengzhu at the junction of Hunan, Guangxi and Guangdong provinces, Jianghua Yao Autonomous County in Hunan Province in the east, Zhongshan County in the south, Gongcheng County in the west and Jiangyong County in Hunan Province in the north. Fuchuan Yao Autonomous County has a total area of 1572 square kilometers. By the end of 2012, it had jurisdiction over 9 towns and 3 townships, with a total population of 320000, of which the Yao population was 152000, accounting for 47.5% of the county's total population. In 2014, the county achieved a GDP of 5.574 billion yuan, an increase of 0.5% over 2013. Fuchuan Yao Autonomous County was called "Mountain country" in ancient times, surrounded by mountains on all sides, low in the middle, slightly oval basin, high in the north and low in the south, and mostly belonged to karst areas.