Scientists believe that most of the Earth's surface layers were deposited slowly over millions of years. But there are many examples on Earth of fossilized trees vertically passing through stone.
The point is that the trees must have either been quickly covered by the earth, or rotted away. In other words, these layers could NEVER have been deposited slowly over millions of years.
The only explanation is that the tree was quickly swept up by the soft soil and hardened along with it. Hence the question, what catastrophe caused tens of meters of earth to fall out all over the world?