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.
Taicang City, a county-level city hosted by Suzhou City in Jiangsu Province, is located in the southeast of Jiangsu Province, on the south bank of the Yangtze River Estuary. It is bordered by the Yangtze River to the east, across the river from Chongming District, Baoshan District and Jiading District of Shanghai to the south, Kunshan City to the west and Changshu City to the north. The total area of the city is 823 square kilometers, the water area of the Yangtze River is 143.97 square kilometers, and the land area is 665.96 square kilometers. It has jurisdiction over 1 street, 6 towns and Taicang Port Economic Development Zone. Taicang culture belongs to Wu Yue culture, Taicang people belong to Jiangsu and Zhejiang people, and use Wu language. Taicang, as the nearest city to Shanghai, has formed the "co-city effect" of geographical proximity, popularity, economic integration and language and culture in Shanghai for a long time. Taicang is close to Shanghai and becomes the "back garden" of Shanghai. Taicang belongs to the subtropical monsoon area with four distinct seasons.