Layered rock at Gusev?

http://marsrovers.jpl.nasa.gov/galle...0P2598L3M1.JPG

Left Panoramic Camera Non-linearized Full frame EDR acquired on Sol 40
of Spirit's mission to Gusev Crater at approximately 09:56:43 Mars
local solar time, camera commanded to use Filter 3 (20 nm).
NASA/JPL/Cornell