Elevation data from the Mars Orbital Laser Altimeter (MOLA) instrument on the Mars Global Surveyor spacecraft shows that the regional terrain slopes gently downward to the northwest, with the highest elevation about 3.5 km (3,500 m) above datum (Mars sea level) on the western flank of the Alba Mons volcano in the southeastern portion of the quadrangle. The lowest points in the quadrangle are about 4.5 km below datum (-4,500 m) in Vastitas Borealis in the northwest corner. The regional relief is thus about 8 km, but at a local scale, slopes are very shallow; the portion of Amazonis Planitia in the south central part of the quadrangle contains some of the flattest terrain on the entire planet.