Well, looking at the pictures I'm in a firm belief that the X isn't an X. If you notice, it seems to shape 2 mountains that connect visually in the center of the X. The left mountain is also part of the turtle tail/body. I *think* this means to go over the left mountain, as the turtle tail is it's ridgeline. I believe the symbol above the turtle, the eye looking thing, means to look for something like a round rock on the other side, or it just means that this rock is telling you where to look. The latter is more likely. So my conclusion for this rock is to look on the ridgeline,other side of the left mountain when facing the 2 mountains.
The other rock has another turtle with it's front drivers leg (like that description?) pointing in the same direction as the 2 arrows. There's another arrow connected to a pyramid looking thing pointing the opposite direction. Also, the tail of the turtle seems to be pointing towards a picture of a bed with a round rock/egg on it. I think this means to follow the front drivers leg to a bed. Lay in the bed and you'll see a round rock. The treasure might be at this round rock. This might also be a rock to throw off hunters, so DO NOT MOVE ANYTHING without being immensly cautious. Try brushing the leaves away in the direction the arrows are pointing to see if there is any kind of trail or anything there. Another thing that seems a touch strange is this turtles rear passenger leg is nubbed off it seems. Not sure about that one yet.
Another thing you might try, if there is a river in the same shape as the one with the N connected to it on the fn rock, is try walking the shape of the N from the river where the N connects to it. See if there is anything there. The shape of the river should give you an idea how far to walk. Keep things in relative relation to their size on the rock.
Take some more pictures of you find things (without revealing the location of the site) and send me to me for resizing if you need to. Whatever program your using to resize images is leaving a big white area at the bottom of them. I have photoshop
In summary, look for the 2 mountains, go up the left one and look for a bed or any other markings. If you find the bed, lay in it and see what you see. Maybe a rock with an egg or something similar. Also, try walking the N connected to the river. Going North from that point on the river is way too obvious, and dosen't seem to fit the rest of the maps. Also brush away leaves in direction of 2 arrows/front drivers leg.
Good luck, and most of all be VERY CAREFULL.