"My observation is this, parts of the Rocky Mountains in Colorado have been under the sea several times. Take a drive up Rt 141 through the Unaweep canyon and visit Colorado National Monument for a great geological lesson. You can see the white bands of rock that were the sea floor. They currently sit around 4,500 feet above sea level. We didn't cause that. The earth has never stopped changing and no organism that was here when it started is still here in the same form. "
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We've been down that canyon but went south around. Very scenic after a rain storm with many waterfalls. I really recommend McPhee's
Annals of an Ancient WorldHe starts on I80 at the eastern end and in a series of books follows it all the way west, each book includes a different geologist who reveals how that section of the country came to be in it's present state. All of the books are included in the above volume. Basin and Range for the mountains of Nevada and Assembling California for how that state came to be.
McPhee is an excellent writer who does all this in very readable language for the average reader. And the geologists he links up to are all field geologists and fascinating people.