That's one of the learning opportunities we often miss when we're outdoors.  Especially in Hill Country looking at rocks, minerals, or fossils, and sometimes arrowheads (though some landowners may not allow the keeping of any of these things) can be a real time of education with younger hunters.

I have just gotten my family interested in being a rock hound. On our recent trip this last weekend (7/11-7/13) my wife found what we think is petrified coral. It is an ivory color with dark blotches on the bottom. A couple of months ago, my grandson, Korbin, found what I think is to be a petrified sponge. It is very light, porous, and has an orange tinge to it. We have found many rocks with seashells embedded in them. We always ask, just how long ago was the Edwards Plateau an ocean? Then my brother brings up a documentary he saw in National Geographic Channel about how the Gulf of Mexico was formed by a meteor that was 6 miles wide. Could this be the answer. Sure makes it worthwhile to look down and turn rocks over. You will never know what you will find.