Very nice! Those rocks in the foreground are indeed very good.
If you’re looking for a little critique, though, I think the cluster of trees on the island look a little “flat”. It might help to use a kneaded eraser and very gently lighten the shading on one side of each tree. Getting something like that right is incredibly hard, though, and you’ve done a good job already.
You also might also get a dirty tortillion and rub in some clouds at the top (I’m guessing it was cloudy…).
BTW, I also really like the mountains in the background, the way they just barely contrast with the pure white of the paper.