Some Tubular Fossils (Sphenothallus: "Vermes") from the Middle and Late Paleozoic of the United States
Specimens of Sphenothallus are reported herein from Devonian through Pennsylvanian age rocks in Iowa, Kentucky, Missouri, Ohio, and West Virginia. Although this form, presumably an annelid, is well known in the Carboniferous of western Europe, Sphenothallus has rarely been cited in the American literature; specimens under other names have been noted in the middle and late Paleozoic of North America but as rare forms, though they appear to be both common and widespread. These phosphatic tubes have been strongly affected by postmortem events, and it is difficult to determine what features should be used as specific characters. Three taxa are informally recognized in the material studied. Sphenothallus was gregarious and was limited to marine environments. One occurrence is of tubes attached to a fragment
Journal of Paleontology, Vol. 59, No. 1 (Jan., 1985), pp. 85-95.