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.
Yongkang, known as Lizhou in ancient times, is in charge of county-level cities in Jinhua City, Zhejiang Province, which is located in the low mountain and hilly areas in the middle of Zhejiang Province. No. 15 Jincheng Road, Dongcheng Street, Municipal people's Government. According to legend, in the eighth year of Wu Chiwu of the three Kingdoms (AD 245), Sun Quan's mother came here for incense because of illness and prayed for "everlasting health." when his wife recovered from her illness, Sun Quan was delighted, so he gave it the name "Yongkang" and established it as a county alone. He was promoted to a state in the Tang Dynasty. In 1992, with the approval of the State Council, counties were withdrawn and cities were established. It has jurisdiction over 10 towns, 4 streets and 1 economic development zone. In June 2017, Yongkang City was named as a national health city. In November 2018, it was selected into the top 100 industrial counties (cities) and Chinese cities in the top 100 in the overall well-off index in 2018. In December 2018, it was selected as one of the top 100 comprehensive competitiveness of county economy in China.