Below is the link to the Earth Science textbook
Printice Hall Earth Science (The main book)
http://www.phschool.com/webcodes10/index.cfm?fuseaction=home.gotoWebCode&wcprefix=cuk&wcsuffix=9999
Holt Environmental Science
http://www.nexuslearning.net/books/Holt_Env_Science/6-2.pdf