I suspect that you have run into a situation where you have a fairly high dynamic range in your images - in the first one, the camera is probably reading more of the sky and thus, the rocks are slightly underexposed, whereas in the second one, the rocks look a little over exposed. Sometimes these situations can be over come with the use of a graduated neutral density filter, sometimes not. Another approach is the use of HDR to cover the dynamic range in the images. Not sure which post-processing software you have, but some of this can be fixed in both Lightroom and Photoshop and probably in Photoshop Elements as well (assuming you shoot raw).
From a compositional perspective, I like the first one...horizon is level and in the lower third position and the "monuments" are in the right and left "thirds" positions. If it were mine, I would try some additional processing and frame it for my wall. The second one does nothing for me, sorry, but that may just be me - don't know. It is not clear what you are trying to show - something in the sky, or something in the rocks...regardless, it just doesn't do anything for me. My 0.02¢.
Cheers,
WesternGuy