Remember about mountains: what they are made of is not what made them. - John McPhee

If you lack confidence in setting one word after another and sense that you are stuck in a place from which you will never be set free, if you feel sure that you will never make it and were not cut out to do this, if your prose seems stillborn and you completely lack confidence, you must be a writer.

A quarter-horse jockey learns to think of a twenty-second race as if it were occurring across twenty minutes — in distinct parts, spaced in his consciousness. Each nuance of the ride comes to him as he builds his race. If you can do the opposite with deep time, living in it and thinking in it until the large numbers settle into place, you can sense how swiftly the initial earth packed itself together, how swiftly continents have assembled and come apart, how far and rapidly continents travel, how quickly mountains rise and how quickly they disintegrate and disappear.

In six thousand years, you could never grow wings on a reptile. With sixty million, however, you could have feathers, too.