Fig. 2. Darker, cross-bedded sandstones such as those shown here lie above the fine-grained mudstones that form the basal layer of Aeolis Mons. Higher levels of the western flank of the mountain appear in the background. Curiosity took the images in this mosaic on sol 1003 (2 June 2015). Credit: NASA/JPL-Caltech/MSSS.