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.
Jinfeng District, established on November 1, 2002, is one of the municipal districts of Yinchuan, the capital of Ningxia Hui Autonomous region. It is located in the middle of the city, with Tanglaiqu in the east, Baolan Railway in the west, Yongning County in the south, Helan County in the north, Liangtian and Fengdeng towns in the north, Shanghai West Road, Beijing Middle Road, Great Wall Middle Road, Mancheng North Street and East Yellow River Road. The District people's Government is stationed on the East Yellow River Road. 2009 the population of the area is 288500, with a total area of 263 square kilometers, including 22000 mu of lakes and wetlands. The party committee, government, people's Congress, CPPCC and other organs of Yinchuan are located in the municipal administrative center on the north side of the people's Square in Jinfeng District. In 2007, the regional GDP reached 4.44 billion yuan, an increase of 14.3% over 2006.