In this case we end up with what we call an apparent polar wander path.
Over time from back when to the present time the pole moved in that direction.
A geologist armed with a magnetometer could sample down through the layers of solidified lava and thus track the direction and intensity of the field over the span of geologic time recorded by that volcano.
datingcambodia com - Paleomagnetism dating websites
This is in the opposite direction of the one we constructed before.
This volcano erupts from time to time, and when its lava solidifies and cools, it records the direction of the Earth's magnetic field.
The pole could not be in two places at once, and furthermore the ocean floors all recorded either north or south, but not directions in between.
So how could lavas of the same age on different land masses show historic directions of the north pole differently from each other?
Once seafloor spreading was recognized as a viable mechanism for moving the lithosphere, geologists realized that these "apparent polar wander paths" could be used to reconstruct the past motions of the continents, using the assumption that the pole was always in about the same place (except during reversals). Because the Earth is a round body in a dipole field, the inclination is directly dependent on latitude.