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.
Haizhu District is located in the middle of Guangzhou, adjacent to Liwan District, Yuexiu District and Tianhe District across the Pearl River in the north, and Huangpu District, Liwan District (including Fang Village) and Panyu District in the east, west and south, respectively, with a total area of 90.40 square kilometers. The main body of the area is Haizhu Island and Henan Island, as well as Guanzhou Island and Yajisha Island. In 2017, the GDP of Haizhu District reached 173.793 billion yuan, an increase of 7.6 percent at comparable prices, of which the added value of the primary industry was 63 million yuan, down 8.3 percent; the added value of the secondary industry was 24.736 billion yuan, up 39.2 percent; and the added value of the tertiary industry was 148.994 billion yuan, an increase of 2.5 percent. With an economic density of 1.922 billion yuan per square kilometer, it has jurisdiction over 18 administrative streets and 265 community neighborhood committees