Sinus Sabaeus: The site lies in a 25-km impact crater in ancient cratered terrain. One well-developed valley system and several smaller valleys drain into the crater, so it probably was a site of ancient aqueous sedimentation. No clear evidence for subsequent volcanic filling of the crater is seen.The site lies less than 100 km from "White Rock," an unusual high-albedo crater floor deposit that has been guessed by some to be a possible carbonate or evaporite deposit.