Right, I’m just going to jump in and say this now before some tin foil hat-wearing, X-Files obsessed, parents basement-dwelling, conspiracy theory-believing fruit loop posts it on their badly designed website and announces to the world what they’ve “found”, and/or what NASA is “covering up”, ok?
Look at the rock at the bottom of this picture…
Notice anything funny? Look more closely…
Ok, as the great man said… Listen very carefully, I shall say zees only wance…
THAT IS NOT A FOSSIL!!!!!! THAT IS NOT THE FOSSILISED REMAINS OF SOME ANCIENT MARTIAN SQUID OR GIANT SPIDER!!!! DO NOT – I REPEAT – DO NOT REVEAL TO THE WORLD THAT YOU’VE FOUND PROOF OF NASA COVERING UP EVIDENCE OF LIFE ON MARS!!! THAT’S JUST ROCK!!!!
Ok?
Good. Just enjoy it for what it is – a cool-looking, aeons-old rock on the surface of an alien planet… 🙂
Note: for some proper, informed, scientific insight into what the markings on this rock actually *are* take a look at the comments. Thanks Nahum! 🙂
Update: I love Twitter! After asking for input from any geologists who might Follow me there, I had some fantastic feedback. So, THANK YOU to Matthew Surles ( @minimicrite ) for these links…
…and to Rochelle Buenviaje ( @orcelb) for the information about komatite…
THE GALE GAZETTE 
But… wouldn’t that be the official line in a cover-up? 😉
Nice find! I didn’t even see the spider shape.
A concluding “and a geologist friend told me that rocks like this form by … [insert your favorite hypothesis]” would have rounded out this posting – which now may actually point the moron-o-sphere right towards this thing they may have missed otherwise …
From that (distant) point of view it’s rather difficult to explain what caused this features on the rock, but let’s try to extract some information of the rock:
1. It’s a dark toned rock, so at first I’m guessing it’s not a sedimentary rock and the structures are not related to sedimentation. I would say it’s an igneous rock, maybe basalt.
2. If you take a look at the full Sol 66 panorama, there are more rocks similiar to this one lying on the ground.
3. If the rock is volcanic, it was not formed here, Gale is a big sedimentary basin (at least as far as I can see)
4. If the rock is an igneous rock, the external structure can be related to the sum of differential erosion (the erosion of different part of the rock due to it’s different hardness) and if it was an extrusive rock, for example, the structure could be created by the flow of the lava while it was getting cold.
But at this point, I think we need a closer look at the rock. If you need some more help, don’t heasistate to contact me 🙂
I’m pretty sure it was Michelle of the Resistance who said “Listen very carefully…” but that’s just splitting hairs 😉
Oops! Thanks!
Here is my take on Sol 64- I’ve added some highlights to some interesting geology you can click on and zoom in.
http://photosynth.net/view.aspx?cid=36952c05-441e-4463-9999-22a12e0fbb64