Figure 1

NASA's Mars Exploration Rover Spirit has examined the layered structure of this rock, called "Tetl," in the "Columbia Hills." This approximately true-color view was made from frames taken by Spirit's panoramic camera on the rover's 264th martian day (Sept. 29, 2004). The rock is about 25 centimeters (10 inches) long. Spirit used its microscopic imager to inspect the region indicated as MI (Figure 1).