The small marine tubeworm, Spirorbis, is abundant in the fossil record. No member of this genus is found in a fresh water habitat. Since Spirorbis tubes are found as a constituent of Carboniferous coal, they are strong evidence for the allochthonous, or transported, origin of much of the coal. This is contrary to the presently popular view that coal originated in swamps and marshes due to the accumulation of plant materials over long periods of time.