Roy, it is good that you realize there are other things to look for besides just gold. Keep your eyes open for fossils, cutting rock, minerals, ore bodies, relics, artifacts, geodes, etc.
I was a rock hound before getting into gold mining and have many books on this subject. The book I believe that will help you the most is " The Audubon Society Field Guide to North American Rocks and Minerals " published in 1978 and has great color photos.
If you are interested in the identification of minerals that are of commercial value ( ore bodies ) then a great book to have is " Introductory Prospecting and Mining " by Leo Mark Anthony, seventh revised edition 1982 University of Alaska. Ron