| Clues, can't fault something that isn't already there, and if the fault stops abruptly at a horizon, that horizon post-dates the fault.
Similarly, you can't intrude something unless it was laready there.
Typically flows (basalts) are found at the surface. Note the absence of contact metamorphism above the basalt, but the presence of contact alteration below and along the sides of the feeder dike.
This is really quite simple a problem if you take a bit of time to think about it. |