Floating Rocks and Plateau Concept

I don't like this one too much. I am having trouble reproducing scale on a large level. The rocks all look like pebbles, their is no sense of depth. I need to work more on the textures to increase the detail, and therefore increasing the scale.

This represents the expedition walking through the mountains that lead to the plateau, and as they walk through the mystical landscape, they come across a giant dinosaur hunting around the floating rocks. I have made a few initial shapes to try and get the right pose, all comments are welcome.

So here is some work in progress:

 Blogger is really annoying me with its lack of precision when placing pictures.

Here is some of the beast sketchs:

C&C welcome.