Cambrian [Marjuman] trilobites (Arthropoda) of the Cow Head, western Newfoundland.

Abstract

Conglomerates consisting of shelf-derived limestone boulders in debris flows form the fossiliferous strata of the Cow Head Group on the west coast of Newfoundland. These conglomerates have yielded in excess of 20,000 trilobites dated from mid-Cambrian into Ordovician. This study examines 1500 specimens of those trilobites in the order Ptychopariida from the earliest Upper Cambrian, the Marjuman. The Upper and Lower Marjuman are distinctly different, with only 3 genera appearing in both. Each boulder comprises a separate collection and the faunas of most are unique.

Ptychoparioid trilobites are found in 15 boulders of the Upper Marjuman and 54 in the Lower. The Upper Marjuman has yielded 21 genera and 37 species, the Lower Marjuman 18 genera and 35 species. Of those, 1 family, 2 genera and 14 species in the Lower are new: the Dineidae fam. nov., Dinea and Rogeraspis gen. nov., and Brassicacephalus rhakion, Bynumia demissa, Dinea bovicephala, D. extremis, Eldoradia batilla, Holmdalia stenis, Kingstonioides delgada, K. grandilabra, Matania brachys, M. catherinae, M. hueva, M. liamae, Prolonchocephalus orcinus and Rogeraspis burkhalteri, sp. nov. In the Upper Marjuman, 1 genus, Kindleia gen. nov., and 9 species are new: Cedaria curta, C. fedora, C. superficialis, Deiracephalus genior, D. intersectus, D. ornatus, Kindleia williamae, Lecanopleura habros, and Matania kindlensis. Fifty-three plates document these and other taxa. Correlation is obtained by comparison with fauna lists reported by Lochman, Palmer and others. Westrop, Ludvigsen and Kindle established an excellent base with their analysis of Agnostoids of the Cow Head upon which this correlation is built. Others are working on the brachiopods. The project will be finalized when the remaining order, the Corynexochida, are documented and incorporated into the correlations.