Well-preserved Late Cambrian radiolarian faunas were recovered from carbonate rocks of the Cow Head Group of the Great Northern Peninsula of the island of Newfoundland, Canada. Several different faunal assemblages were recognized from three strata at Green Point, one from a stratum at Martin Point, and three from strata at Broom Point South in Gros Morne National Park. The faunas contain nine genera, five of which are new, and 33 species, all but two of which are new. The five new genera are Curvechidnina, Grosmorneus, Pararcheoentactinia, Ramuspiculum, and Subechidnina. Most of the genera belong to the families Archeoentactinidae, Echidninidae, Palaeospiculumidae, and Protoentactiniidae; a few taxa have an uncertain taxonomic position. Echidnina, whose taxonomic identity was uncertain, is shown to be a radiolarian.
The diversity of each of these faunas is similar, but the difference in faunal compositions among the faunas examined is distinct. From this analysis, the Late Cambrian strata between Martin Point and Green Point can be more precisely correlated, and the previous correlation has been revised. With the recovery of the conodonts in this study, the provisionally placed boundary between the Franconian and Trempealeauan at Martin Point by earlier researchers is revised and positioned between unit 30 and unit 31.
The biostratigraphic range of the co-occurring conodonts indicates that the youngest fauna described in this paper belongs to the Eoconodontus notchpeakensis Zone of late Trempealeauan age and that the other faunas (from Martin Point and Green Point) are of Franconian age.