Brachiopodes du Dévonien Inférieur et Moyen des formations de Blue Fiord et Bird Fiord des Îles Arctiques Canadiennes
Authors: Brice D 
Published: August 2015

The brachiopods (Pentamerida, Rhynchonellida, Spiriferidina) that are described and illustrated are from the Blue Fiord, Bird Fiord and comparable formations of the Canadian Arc tic Islands, principally from Ellesmere, Devon and Bathurst Islands. The brachiopods
were selected from numerous collections of fossils made by the Geological Survey of Canada during Operation Franklin (1955) and in subsequent field studies.
The brachiopod faunas obviously are st rongly endemic in character; of the more than thirty species or subspecies identified, ten belong to genera or subgenera of limited geographic provenance, twenty-five are restricted to the Arctic and among these, twenty-one are new taxa. These are: Pentamerida:
Carinagypa (Aseptagypa) maclareni, Ivdelinia grinnellensis, I. (Ivdelinella) ellesmerensis; Rhynchonellida: Ancillotoechia? ventricosa variabilis, Cupularostrum? pentagonale, C. ? ellesmerense, Camarotoechia s. l. pseudomedea, Hypothyridina bifurcata, Cassidirostrum vexans arcticum, Athyrhynchus
susanae intermedius, A. sverdrupi eosverdrupi, A. trilobatus; Spiriferidina: Fimbrispirifer? pseudoscheii, F. fascicostatus, Warrenella disjuncta, W. franklini praefranklini (typical and transverse forms), W. collina arctica, W. pseudaequabilis, W. (Warrenellina) extensa, Emanuella bisiruata,
Elythina sverdrupi. A considerable number of forms at present remain generically or specifically undetermined, because of insufficient material to allow reliable determination.
The faunas of the two formations, especially that of the lower part of Blue Fiord Formation, clearly are related to Nevada faunas. At the close -of the Early Devonian, the Arctic Islands belonged to the same faunal province as Nevada and the Yukon. This province has been named the Cordilleran
subprovince by Boucot et al. (1967) and considered by them to be a subprovince of the Old World Province. This connection between the Arctic Islands and Nevada continued at least for a part of the Middle Devonian, that is until the close of Blue Fiord sedimentation. These conclusions are deduced
from the appearance at certain times of a number of common genera or species in the faunas of the two regions. These same elements are used to establish the following correlations which form the prime evidence of the ages of the rock units: (1) the Nevada zone of Eurekaspirif er pinyonensis (dated
as Emsien) with the lower part of the lower member of the Blue Fiord Formation in the type locality; (2) the Nevada Zone of Leptathyris circula and the lower part of that of Warrenella kirki (dated as Eifelien) with the upper part of the lower member and the lower part of the upper member of Blue
Fiord Formation in the type locality.

The age of the Blue Fiord Formation at its type locality and in the other areas in which it outcrops is deduced principally from these correlations.
The Bird Fiord Formation is dated at its type locality and in other parts of Devon and Ellesmere Islands as probably Late Eifelien but as probably Givetien in Bathurst Island, inferred principally from the distribution of certain brachiopod genera (Ivdelinia, Hypothyridina, Cupularostrum and
Elythina).
Among the representatives of these three groups of brachiopods, some elements show relationships with faunas from northeastern Russia, while some others have Appalachian or European affinities. The distribution of species within the Blue Fiord and Bird Fiord Formations at their type localities
provides a basis to discuss !and in some cases to make more precise) correlations previously proposed by authors between these sections and rock units at other localities in the Arctic Islands where these formations have been reported.