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.
Zijin County, which belongs to Heyuan City, Guangdong Province, is located in the east and middle of Guangdong Province, the southeast of Heyuan City, and the east bank of the middle reaches of Dongjiang River. Between longitude 114o 40mm / m 115 °30m east and latitude 23 °10m / m 23o 45' north. The county is 88.6km long from east to west and 64km wide from north to south, with a total area of 3627 square kilometers. Zijin County is located in the subtropical monsoon climate zone. The climate is mild, with plenty of light and rainfall. As of 2018, Zijin County has jurisdiction over 18 towns, 273 village committees, 27 community neighborhood committees, 4410 villagers' groups and 4410 resident groups (including Guzhu Town and Linjiang Town, Jiangdong New area). The county government is stationed in Zicheng. Zijin County has been inhabited by human beings in the Neolithic Age. After the Qin and Han dynasties, the Han nationality in the Central Plains gradually moved southward, with the local minority.