Catt, you started this in 08 and it is still going. Thanks for the info. But....................you didn't finish the original topic. All lakes have it. Humps, points, ridges, roadbeds, are not in all lakes. So, since I have been copying and pasteing for the past three days, I must assume that there is more to this topic and it has slipped away from your lesson plan. Or, you feel that this is a completed subject and you are waiting for the students to tell you their answers. Water, would not be the correct answer, and since some lakes don't have points and some don't have humps and some don't have roadbeds, ect. I suppose that would make the answer ???? Structure? Again, thank you. I have not been a member on BR long, but this is the most informative site there is.