Trap dikes may be either absent of very rare in coal-bearing sequences. Of course their presence is important for paleomagnetic studies.
dykes in coal bearing strata are not frequent but trap in such sequence can be inferred if you have good control of the chronological and tectonic frame work of the area you are interested.
Since coal deposits mark extensive tropical forests that occupied platform areas, there would be far from rifts with intrusive/extrusive rocks at the time. Later developments, however, could introduce a newly formed rift just about anywhere including this platform.
Dear Michael,
I think that this is the correct answer. It is an odd occurrence in Pennsylvanian coal-bearing deposits of the Narragansett Basin of New England, U.S.A. The trap I think is of Triassic or Jurassic in age and is associated witht he rift basins that developed later in New England such as in the Connecticut River Valley.
I recommend Michael for a thumbs up for what I believe is the correct answer.