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.
Xiajin County, which belongs to Dezhou City, Shandong Province, gets its name from "the important Jin of the Qi-Jin Union". It is located in the northwest plain of Shandong and the junction of Shandong and Hebei provinces. Texas in the north, Liaocheng in the south and the Beijing-Hangzhou Grand Canal in the west. As of 2018, Xiajin County has jurisdiction over 10 towns, 2 townships, 1 street and 1 provincial development zone, 314 communities, with a total area of 882square kilometers, cultivated land of 900000 mu and a resident population of 519600 at the end of 2018. Xia Jin is called "Yancheng" in ancient times, which has a history of more than 2200 years. Deshang Expressway, Qingyin Expressway, National Highway 308, Provincial Highway 254 and 315 crisscross, running through the whole territory of Xiajin County. Xiajin County has a total area of 128000 mu of original ecological forest resources along the old route of the Yellow River, which is a national AAAA tourist scenic spot, a national forest park and a national holiday.