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.
Fengkai County, which belongs to Zhaoqing City, Guangdong Province, is located in the northwest of Guangdong Province. It is not only an important part of the "Xijiang Corridor" economic region, but also the intersection of the "Pearl River Delta" and the southwest. It is between 23 °13 north latitude & #39;-23 °59-#39;, east longitude 111o 21-#39;-112 °02-#39;, with a total area of 2723.93 square kilometers. Fengkai is a mountainous and hilly area, with high mountains in the east and hills in the west, with terrain from east to west, concave in the middle and low in the north and south. Belongs to the subtropical monsoon humid climate. Affected by the monsoon, the climate is warm, the winter is short and the summer is long, and the frost-free period is long. As of 2017, Fengkai County has jurisdiction over 16 towns, with a resident population of 414500 and a registered permanent population of 522000. County