QUESTION:
So far, there are only two APXS analyses of good solid rocks on the Science
Results page of the Pathfinder website.  Both of these (after correction for
dust) fall pretty much in the andesite field of the alkalis vs. silica plot. 
What about all the other rocks that Sojourner has visited (Wedge, Shark,
Halfdome, Moe and the rest)? Do their compsitions look much the same? If
not, what range of compositions has been found?

ANSWER from Wendy Calvin on October 31, 1997:
Well, I am not connected with the APXS instrument, but from what I have seen
presented, most of the rocks analyzed are similar in composition and fall in
the "Basaltic-Andesite" regime. There are certainly no rocks that come close
to the basaltic composition of the SNCs.

Wendy