#Plate tectonics
Megan,
You'll probably find a discussion of plate tectonics in any good book on
prehistoric life, especially one published in the last decade or so. My
paleontology reference textbook, EARTH AND LIFE THROUGH TIME, has sections on
each period of Earth history, and in each section there's at least one diagram
of what the continents looked like at that time.
Also, if you have a CD-ROM, at least some of the encyclopedias around have
animations of continental drift.
Jon W.