Spirit is real close to the hills now. The Sol 154 pics are well worth checking out! Definitely seem to be some bedrock exposures up on the heights.

Even more intriguing, is that it looks like there may be some faint outcrops nearby:

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If you look at the upper right, there's a light-colored linear feature that runs from the vertical center to the right edge, like a little exposed ridge. Seems too continuous and too narrow to be a random cluster of rocks, plus sort of seems to be some subparallel features in the slope above it. Or perhaps it is just some stones on a wind-carved rise; I haven't made a 3D image out of the pair and so maybe I'm reading the terrain wrong.

I'm having trouble correlating that pancam image with any of today's navcam images for context.

This navcam image also has some suggestive features on the slight slope in the middle-near distance.

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If those are outcrops I imagine they are just basalt, but I'm sure there's still value in finding the orginal beds. Yet again, I long for an age-dating method you could carry on a rover -- basalt *would* be exicting if you could get ages on a sequence of flows/intrusions.

In general you can see the rock abundance going way up, as the orbital data predicted. Looking at the ground ahead in the navcam images, it starts to look more like a gravel/cobble surface (excuse any implied weathering -- I just mean small rocks) smoothed and filled in by soil instead of mostly soil with rocks mixed in.