South Korea most of which is not arable. Lowlands, located primarily in the west and southeast, make up only 30% of the total land area. About three thousand islands, mostly small and uninhabited, lie off the western and southern coasts of South Korea. Jeju-do is about off the southern coast of South Korea. It is the country's largest island, with an area of . Jeju is also the site of South Korea's highest point: Hallasan, an extinct volcano, reaches above sea level. The easternmost islands of South Korea include Ulleungdo and Liancourt Rocks (Dokdo/Takeshima), while Marado and Socotra Rock are the southernmost
Jackson Volcano limestone. The structure was noticed by Hopkins in 1917 and a successful gas well was drilled in 1930, but the field was nearly exhausted by 1939. Jackson Volcano ash within the Eutaw Formation produces oil in the Tinsley Oil Field, where oil was first discovered in the Woodruff Sandstone (Selma Chalk), an eroded sand from Jackson. Jackson Volcano Jackson Volcano is an extinct volcano beneath the city of Jackson, Mississippi, under the Mississippi Coliseum. The uplifted terrain around the volcano forms the Jackson Dome, an area of dense rock clearly noticeable in local gravity measurements. E.W. Hilgard published his theory