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.
Huludao, a prefecture-level city of Liaoning Province, is located on the western coast of Liaoning Province, with a central geographical position of 120 °38` east longitude and 40 °56` north latitude, adjacent to Jinzhou in the east, Shanhaiguan in the west, Bohai Bay in the south and Chaoyang in the north. Dalian, Yingkou, Qinhuangdao, Qingdao and other cities constitute the Bohai Economic Circle, which is an important gateway for Northeast China to enter the customs. By the end of 2018, Huludao City has a total area of 10400 square kilometers, including 3 districts, 2 counties and 1 city, with a total population of 2.764 million. Huludao City, formerly known as Jinxi City, was upgraded to a municipality under the provincial government in 1989, with a continental monsoon climate in the north temperate zone; with mountains and seas, the terrain gradually decreased from northwest to southeast. There are Beijing-Harbin Highway, G1 Beijing-Harbin Expressway, Shenshan Railway and Beijing-Harbin Railway in Huludao.