Book Review: Valleys and Canyons

Valley and Canyons by Larry Dane Brimmer, Grolier Publishing, New York, 2000.
This is a geology book rather than history; but my thought is geology is just ancient history, at least history of the rocks and natural world. 
This is a youth book.  It explains in a simple way where canyons and valleys come from.  Of course there are no canyons or valleys without mountains.  There are many causes of valleys and canyons.  Glaciers create U shaped valleys, while water and wind create a more V shaped valley.  Rift Valleys are formed by faulting action.  Often the valley sinks while the mountains rise.  This are called rift valleys.  There is a large one in Africa; but the largest is under the ocean.  Valleys under water are called submarine valleys.
The crust of the earth, sitting upon a molten core, and moving as it does, creates mountain and valley action.  When the mountain is forced up, the part left down becomes a valley.  Volcanoes also contribute to mountains being formed.