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.
The new urban area, together with the national Urumqi High-tech Industrial Development Zone, implements & quot; District political Integration & quot; system, which belongs to Urumqi City of Xinjiang Uygur Autonomous region and is located in the northwest of Urumqi City. It is 14 km long from east to west and 9 km wide from north to south. The total area of the new urban area is 143sq km, with a total population of 379220 (2000). The new urban area has jurisdiction over 1 town, 4 townships and 13 streets, inhabited by 38 ethnic groups such as Han, Uygur and Hui. In the area under its jurisdiction, there are more than 500 units of the central government, autonomous regions, troops stationed in Ukraine, the Armed Police Force, the production and Construction Corps, and more than 20 scientific research institutes such as the Xinjiang Branch of the Chinese Academy of Sciences and the Xinjiang Academy of Social Sciences. There are 33 colleges and universities, such as Xinjiang Medical University and Xinjiang University of Finance and Economics. The new urban area is the pass.