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.
Cuona County, Tibetan: in Tibetan, it means "in front of the lake". It belongs to Shannan City and Xia County of Shannan City, Tibet Autonomous region. it is located at the southern end of Tibet Autonomous region, at the southern foot of the Himalayas, between 91 °28 °22 'east longitude and 26 °25 °28 °27' north latitude. Bordered by India and Luoyu to the east, Bhutan to the west and India to the south, it is one of the border counties of the Tibet Autonomous region. The county covers an area of 34979 square kilometers (controlled area of about 10094 square kilometers). Cuona County is the hometown of Cangyang Gyatso, which is rich in tourism resources. In 2013, the county completed 356.19 million yuan in GDP, 528.27 million yuan in investment in fixed assets, 12.94 million yuan in revenue and zero in consumer goods.