As mentioned before, I'm a bit of a geology buff -- but far from being an expert. We began our two-day train trip across Western Canada on the dry side of the mountains. That will be obvious enough from these photos. I was impressed by all the outcrops, upthrusts and places where erosion shows us what lies beneath the surface.
In this picture, notice the different colors in the rock: iron and copper for sure, but there are probably others. Marc's the chemist in the family, I'm sure he could tell us more.
Here, you can see a bit of outcropping where the soil has been eroded away to show the rock beneath.
Here's another example.
Mountains are formed in a couple of different ways. These are "upthrust" mountains formed when two tectonic plates press against each other and causes "wrinkles". You can see how the rock has been pushed up at an angle.
I love this shot that shows the different types and colors of rocks exposed by the water's cutting path.