Okay, I did a quick test on the central mountain range. I'm at work now, so I can't use my drawing tablet to add the shading just yet, but I managed to at least recreate the mountain range with smaller mountains. Below you can find the "old" mountains on the left, and the new (as yet unshaded) ones on the right. Let me know which of the two you prefer!

Click image for larger version. 

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ID:	60184 Click image for larger version. 

Name:	mountains_new.jpg 
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ID:	60185

thanks for your comments!
C