The dinosaur is at the last point of extinction. A volcano is erupting. This is how the story starts.
The volcanoes has destroyed everything. Only a little island was left. As you see in the picture, the Stegosaurus body is dissolving. The Stegosaurus is not to be seen, but its fossil is. The fossil is lying on the sand. The fossil is sinking. Sediment covers the fossil. It is now a cast fossil, it is covered in sediment. The pressure of the ground causes the sediment to turn to a sedimentary rock.
Tectonic plates have moved. Because the fossil was in the rock and the fossil was in the crust (tectonic plates), the fossil is in the mountain. Some parts of it's body have been exposed. This is now a body fossil.
The time of man has come. This farmer is digging the grass. He is astonished at what he has found. A dinosaur fossil. He digs a bit more and covers it in plaster.
The man takes the plastered Stegosaurus fossil to the museum.
Another volcano erupts. This time, people will have to dig deeper because the ash will bury the fossils.