Help understanding Latitude and Longitude http://www.learner.org/jnorth/tm/LongitudeIntro.html
Awesome PowerPoint presentation on the 4 Regions of Texas http://www.hipark.austin.isd.tenet.edu/grade4/guimbarda/wes.htm
Though the entire textbook is not available online, this website does provide a brief overview of each section. http://www.celebratetexas.com