This mosaic of images taken by the microscopic imager on the Mars Exploration Rover Opportunity shows the finely-laminated target called "Cobble Hill" at "Endurance Crater." Scientists studying the target have determined that the layers within it are rich in sulfate, like many of the rocks in Endurance and "Eagle Crater" that have been investigated so far. This image comprises four separate microscopic images taken on sol 143 (June 19, 2004). The circle is where the rover's rock abrasion tool cut away the rock's surface to expose the interior. It is 4.5 centimeters (1.8 inches) in diameter.