 Enclosed within the great arc of the Carpathians lie the undulating plains and low hills of the Transylvanian Plateau—the largest tableland in the country and the center of Romania.This important agricultural region also contains large deposits of methane gas and salt.To the south and east of the Carpathians, the Sub-Carpathians form a fringe of rolling terrain ranging from 396 to 1,006 meters in elevation.