Cemetary scene

Yes.

It was because she was "buried on top" of her mother. There was that entire scene about who's on top of each other from the train compartment.

And Craven makes a kind of voiceover reference to how his daughter's coffin is placed in the grave and its relation to his wife's. His daughter wanted to sleep "on top" in the train car. So he made sure she slept on top for eternity....

Fwiw, 'natural' burials are only about a meter deep, since this is the optimal zone for 'recycling'.