Great!
I love crib sheets and this one is terrific. It clearly maps out the time scale of the history of the planet. It gives the names and lengths of its periods and a brief description of why they begin and end when they do. Whether you are reading about the evolution of whales, trilobites, stromatolites or dinosaurs it give a quick and easy perspective of when your subject lived.
It is better than a book because it is always in your pocket.
It is better than a book because it is always in your pocket.
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