mlm wrote in :

You'll find the images at:

http://marsrovers.jpl.nasa.gov/galle...nity_m035.html

Several show the 3/4 berry.

You can't help but get the impression from looking at these MI images
that these berries became lodged in their surrounding matrix at exactly
the same time, during the same event.

Mark

Have a look at

1M131212854EFF0500P2959M2M1.jpg

By chance (could it be by design? -- I doubt it based on the
appearance of the rock prior to grinding), the RAT has cut a partial
cross section of one of the blueberries. Look in the lower left edge
of the RAT abrasion circle. You'll see a blueberry that has been cut
halfway through. THere are clearly no rings in either the x y or z
directions. These things definitely formed at a single instant
(although they may have been shaped at the bottom of a lake over many
centuries). THey did not build up in layers. You can also see there
are no distinct internal structures so these berries would not likely
be biological in origin. They cut (and polish) just like rocks so
they would have to be fairly hard. Possibly fossils or petrified
organic matter if you wanted to really speculate on a biological
origin.

They all are also almost perfect spheres, and remarkably similar in
size -- within a hundred or so microns. Place a circle over any one
of them and you will see it fits very accurately. They are therefore
unlikely to be the product of a meteor splash or volcanic eruption as
this would not result in such uniformly perfect and similarly sized
spheres -- there would be a large number of irregular berries in such
an event, since a splash of molten rock would radiate out along many
trajectories.

This leaves a water-based formation as increasingly likely. Fluvial
erosion is very efficient at producing spherical rocks.

I would guess we are looking at objects which have rolled along
Martian river beds or beaches at the edge of lakes or oceans. Perhaps
later becoming set in sand accumulating and conglomerating with
pressure.

Mark