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.
Baoqing County, which belongs to the escrow County of Shuangyashan City, Heilongjiang Province, is located in the east of Heilongjiang Province, the core of Sanjiang Plain and the hinterland of Beidahuang. the geomorphological features can be summarized as "four mountains, one water and four fields, half Reed and half grassland". The administrative area of Baoqing County covers an area of 10001.27 square kilometers, with a population of 470000 as of 2010. Baoqing County is a typical resource county, agricultural county and ecological county, which is known as "coal power base", "granary of the north", "county of abundance" and "hometown of wetlands". The main scenic spots in Baoqing County are Zhenbao Island Revolutionary Martyrs Mausoleum, Dragon Lake Scenic spot, Dongsheng Wetland Scenic spot, Qixing River Wetland and Yanwo Island. On October 22, 2018, Baoqing County was selected into the list of national pilot areas for the integration and development of primary, secondary and tertiary industries in rural areas in 2018. two hundred and one