Journal of Paleontology; February 2005; v. 79; no. 2;
p. 219-241; DOI: 10.1666/0022-3360(2005)079<0219:MALCGA>2.0.CO;2
© 2005 Paleontological Society
MIDDLE ALBIAN (LOWER CRETACEOUS) GASTROPLITINID AMMONITES AND DINOFLAGELLATES FROM THE CHRISTOPHER FORMATION (DRAGON MOUNTAIN, AXEL HEIBERG ISLAND, CANADIAN ARCTIC ISLANDS) AND A REVISION OF THE GENUS PSEUDOGASTROPLITES JELETZKY, 1980
RUSSELL L. HALL1,
R. ANDREW MACRAE2 and
L. V. HILLS1
1 Department of Geology and Geophysics, University of Calgary, Alberta T2N 1N4, Canada, <hallr{at}ucalgary.ca>
2 Department of Geology, Saint Mary's University, Halifax, Nova Scotia B3H 3C3, Canada, <Andrew.MacRae{at}smu.ca>
A large sample of excellently preserved ammonites from concretions concentrated at a single horizon near the base of the Macdougall Point Member of the Christopher Formation (AptianAlbian age; Early Cretaceous) is the basis for recognizing a new species of the boreal ammonite genus Pseudogastroplites (P. draconensis). The dimorphic nature of the genus is established, two variants are recognized (P. draconensis var. robusta and P. draconensis var. gracile), and the generic diagnosis is emended. Retention of the genus Pseudogastroplites Jeletzky, 1980 as distinct from Gastroplites McLearn, 1930 is proposed. The concretions also yield Pseudopulchellia flexicostata (Imlay, 1961), inoceramid bivalves, fish remains, and a palynological flora, and are dated as late middle Albian.
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