This process, in which the rotation of a planet with an iron core produces a magnetic field, is called a dynamo effect.
The Earth's magnetic core is generally inclined at an 11 degree angle from the Earth's axis of rotation.
So if we are presented with an undated rock, and we find a really distinctive pattern of paleomagnetic reversals within it, we may be able to identify the one time at which such a sequence of magnetic reversals took place.
The reader will observe that it is necessary to be able to date some rocks, in fact a lot of rocks, before paleomagnetic dating can be brought into play.
Therefore, the magnetic north pole is at approximately an 11 degree angle from the geographic north pole.