?? an old dock??

I took this from a different spot up on the bluffs over the Lake, and I was intrigued with this old  (?) dock that looked like 2 huge round cylinders held together by big metal pieces. It's obviously not in use anymore, except by the geese! There are also several trees growing on it which seems almost impossible, as there doesn't seem to be that much dirt covering the top of the cylinders. I thought it made a good entry for derelict sunday. :)