Your normals are looking a little strong in the render. If the edges on the rocks are on their own layer, you can tone them down easily with the opacity. You might need to go as low as 50%, but try around 70% first. What you want to avoid are the black, or nearly black, edges. You can see what I mean around the bottom left hand edge of your render.
Thanks for the comment! I did the changes and added them to the post! :D