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.
Boli County belongs to Qitaihe City, Heilongjiang Province, which is located in the east of Heilongjiang Province. when the county was established, Yilan Daoyin was named with the meaning of "prosperous and smooth". It is located in the east of Heilongjiang Province, bordering with Baoqing, Jidong, Linkou, Yilan and Huanan counties. the geographical coordinates are 130 °6km east longitude and 46 °37km north latitude. The total area of the county is nearly 3000 square kilometers. As of 2013, Boli County has jurisdiction over 5 towns and 5 townships with a total population of 316000. In addition to the Han nationality, there are 14 ethnic minorities, such as Hui, Korean and Manchu. In 2013, Boli County achieved a regional GDP of 5.48 billion yuan, down 19.6% from 2012. It is a national commercial grain base county, a key plantation county, and a fruit tree production base county.