I've been reading an article on the process of fossilization, and a point that is made repeatedly is the slim chance of things becoming fossilized. By far much more works against that process, such as detritivores, than for it. The fact that we do come across significant fossil records is a rare, wonderful gift from nature, no matter how much we might at times take those gifts for granted. Jackie's absolutely right. There is much we will never know through fossil records because so much wasn't ever fossilized. Taphonomy. It's a very interesting subject to read about.