1.- A numerical date means a specific number of years that have passed since a ceratin event.
3.- They will show geological events that are really important historically, they will also help us identify the periods of time that are missing from the record.
4.- Angular conformity: Underlying rocks are tilted sideways before formation of the erosion surface
Disconformity: If rock layers are not tilted before younger layers, but the boundary overlap them still represents millions of years of time
Nonconformity: Erosion will be forming on top of rocks that are not layered