March 23, 2004 — Opportunity's new view of the plains of Meridiani Planum shows plentiful ripples, a clear indication that wind is the primary geologic process currently in effect on the plains. On the left of the image are two depressions, each about a meter (about 3.3 feet) across, that feature bright spots in their centers. One possibility is that the bright material is similar in composition to the rocks in Eagle Crater's outcrop and the surrounding darker material is what's referred to as lag deposit, or erosional remnants that are much harder and more difficult to wear away. These twin dimples might be revealing pieces of a larger outcrop that lies beneath.