leftovers
Looks liked perched blocks of a layer that is mostly gone now. It's dark, but that's part filter. If I'm reading the file name correctly, that's the #R7 filter, way out of normal vision (980 nm low pass - Far IR). I'm looking forward to a stereo nav-cam view or the color blend from the pancam.
Of course I'm seeing differentially eroded, gently inward-dipping layers in everything Spirit is sending back these days. Model bias to perception...must be wary.