Marks (chapter 11 spoilers?)

I've completed the first eleven and something fancy happened when I got some flying enemy done. I went up a rank and now I figure some more Ci'eth stones should be appearing to give me quests - since I've done 1-11 I figure 12-20 at the least should now be available, surely? I'm a little confused as to how exactly all of this works.

Damn Waterstones for delaying the delivery of my Piggyback guide from 9th March all the way through to, well, whenever it decides to arrive. :(

I've having trouble finding Cie'th stones, and we've only completed a few!

If you're having trouble finding them, make sure you take a good look around that map at the other end of the base camp (I forget the name), there's a good amount of stuff there.