Mars Lifesaver?

What on Mars is this?  A lifesaver for little people?  An old tire or tube off a '57 Chevy?  A nautilus?  Or maybe Spirit brought this item with it?  (That's usually what NASA says.)   This does not look like a geologic formation to me.

Spirit Image from Sol 54  Original at:  http://marsrovers.jpl.nasa.gov/gallery/all/2/m/054/2M131155133EFF1124P2953M2M1.JPG

I've spent a lot of time examining this photograph.  If you magnify the original, there are several features that seem to come out.  First, if you look within the lifesaver, the large object on the left looks clearly like some sort of oyster.  You can see layers on it just like the ones at Red Lobster.  The other two objects within the inner circle of the lifesaver also appear to be different types of clams and the one on the bottom clearly shows where the two halves would open.  As far as the lifesaver goes, the inner circle seems to show a trace through the soil.

The lifesaver seems to be imbedded in the soil.  Since this is an old lake been, it looks like all of these things were here together when the water finally left.  The lifesaver is partially buried, but as I said, you can see where the inner circle continues completely around.  Only a portion of the outer circle shows.  Also note that there is a third circle, a small impression on the right hand side near where it enters the soil.  This almost appears to be a brand mark or something, like a maple leaf.  The fact that there are three very accurate circles in this picture is suggestive of intelligent life.  Whether that means something from the rover or something on Mars is the question.

The last feature I would like to note, is the apparent multiple layer "construction" of the lifesaver.  As one looks at the shadows and general appearance, there is a strong feeling of three dimensions to the object.  It appears that a layer has worn away in a small spot near the upper right hand side.  The inside material appears much darker, although we may be seeing the dirt underneath the object.  The darker material appears to show through in other places around the rest of the ring.

It has been suggested that this is part of the Spirit Rover, or tracks that it has made.  I don't think this is the case.  This object appears untouched and doesn't show any of the features seen in the rover tracks. See the next photo below.   Also note how well the object is mixed with its environment.  There appears to be small grains of dirt in the "insignia" circle, indicating they have all been in this situation together for a long time.

I've been wondering where the Spirit Rover was, when the last picture was taken.  The four ring pictures above were taken on Sol 54 between 11:00 and 11:04.  The next picture was taken by the Front HazCam at 11:05 showing exactly what was being photographed at that location.  The ring structure is very small.  Here is the location of the above photo.  It appears to be photographing a random location within this small area where the soil is more abundant and we see less rocks.  Also note that the rover has not left any tracks in this picture.  This is the front of the rover and this is the direction the rover is moving.

 http://marsrovers.jpl.nasa.gov/gallery/all/2/f/054/2F131155320EDN1124P1111R0M1.HTML

Three hours later, the Front HazCam on Spirit takes another picture.  This time the rover is nearing its next target, the rock you see in the picture.  The rover has apparently driven during this time, since the scene has changed.  As you can see, the Spirit has moved out the area of fine soil and into the rocky region.

http://marsrovers.jpl.nasa.gov/gallery/all/2/f/054/2F131168111EDN1133P1228L0M1.JPG

This next image from Opportunity is just about as weird.  Is that lichen growing on these rocks?  And what are those round things?  Martian Pearls?   See Clam above in middle of lifesaver.  Below we see cross sections of the pearls, after being cut in half by the RAT.  If we have clams at Spirit and Pearls at Opportunity, things are starting to make sense.  Mars did have oceans.

Image from Opportunity Sol 34  Original at:  http://marsrovers.jpl.nasa.gov/gallery/all/1/m/034/1M131212854EFF0500P2959M2M1.JPG