According to Cardinal Chunder :
These rocks are actually machine parts!
http://www.enterprisemission.com/spirit.htm
It's so obvious - simply toss away the most likely hypothesis (that
these rock-like things are rocks), throw in some paranoia and heavy
picture filtering and suddenly you have proof of the conspiracy!

See, he calls it a conspiracy; I call it proof that martians had nifty
machinery.

--
eth'nT
http://www.hydrous.net
aim: courtarro