This high-resolution image captured by the Mars Exploration rover Opportunity's panoramic camera, Wednesday, Jan. 28, 2004, highlights the puzzling rock outcropping that scientists are eagerly planning to investigate. These layered rocks measure only 4 inches tall and are thought to be either volcanic ash deposits or sediments carried by water or wind. Data from the panoramic camera's near-infrared, blue and green filters were combined to create this approximate, true-color image.