Sigh.
The rock guys aren't so smart after all. I thought from the picture in reply 281 that the scoop had pulled a rock out of position and sampled the soil under the rock.
Yay!
However, a closer examination of a before / after animation shows that the rock was moved only slightly and mostly rotated -- so the soil sample is not from under a rock.
Boo!
It looks like this may simply be the start of another trench.
Have shovel. Will travel: Phoenix
For anyone interested, I did a little study of the contents of the latest scoopful of Super Oxydol soil ( Garan-teed to clean all them dirty Mars bugs from 'yer britches ) here.
Just the same o' same o'