PLIENSBACHIAN (LOWER JURASSIC) BIOSTRATIGRAPHY AND ...

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Discussion. This poorly preserved collection probably contains representatives of Protogrammoceras paltum and P. argutum . Protogrammoceras paltum has been previously reported from the Tulsequah area of northern British Columbia (as Harpoceras sp. cf. H. e x a r a tu m in Frebold, 1964a; Frebold, 1970). Protogram m oceras paltum has a variable morphology as seen in the differences between the holotype (PI. 362a) and paratype (PI. 362b) figured by Buckman (1922). The holotype is less involute and has a more variable (and generally greater) rib density than that of the p a ra ty p e . Som e S p atsizi specim ens of Protogram m oceras spp. have a comparable rib density to that of Buckman’s holotype, but are more involute, as is Buckman’s paratype. These variations in P. paltum have also been observed in collections from Arctic Canada (Hall and Howarth, 1983) and from British Columbia and the Yukon by Frebold (1970), who further stated that the morphological gap between P. paltum and the species P. argutum is bridged by transitional forms. P rotogram m oceras argutum is characterized by its ribbing, which is consistently fine and dense throughout growth. Occurrence. P rotogram m oceras argutum has been collected from north-central British Colum bia (Frebold, 1970), Alaska (Imlay, 1981), and Oregon (Imlay, 1968). It is also known from South America (Hillebrandt, 1987) and is widely distributed in Europe, perhaps being more characteristic of the Mediterranean countries. In all cases it is Late Pliensbachian in age. Protogram m oceras paltum is a widespread species common in Europe and also reported from Japan (Hirano, 1971), Alaska (Imlay, 1981), the Canadian Arctic Archipelago (Hall and Howarth, 1983), and the western Cordillera of Canada (Frebold, 1970). In the Spatsizi area, P rotogram m oceras spp. are found associated with Tiltoniceras pro p in q u u m and rare Fanninoceras, and occur below the first appearance of Dactylioceras, suggesting a Late Pliensbachian age. In the Taku River area of northern British Columbia, P. paltum is found associated with A m altheus (Frebold, 1970), also indicating a Late Pliensbachian age. Hall and H ow arth (1983) have assigned the Arctic specimens of P. paltum to the Upper Pliensbachian (Spinatum Zone) although the evidence is weak. Hall and Howarth (1983) point out that P. paltum has a diachronous distribution. Specimens from the Northwest European province, notably England (Howarth, 1973a) and Luxembourg (Maubeuge and Rioult, 1964), are lowest Toarcian in age. Based on biostratigraphic studies of the succession on the Yorkshire coast, Howarth (1973a) proposed the P. p a ltu m Subzone as the lowest division of the Tenuicostatum Zone. In the Alpine and Mediterranean region of Europe, however, P. p a ltu m is of Late Pliensbachian age, and, as discussed above, P. paltum is of Late Pliensbachian age in North America. The Spatsizi material was found at localities 32, 43, 50, 62, 63, 71, 79, and 102. Age. Late Pliensbachian (Carlottense Zone). REFERENCES Arkell, W.J. 1950: A classification of the Jurassic ammonites. Journal of Paleontology, v. 24, p. 354-369. Arkell, W.J., kummel, B., and Wright, C.W. 1957: Mesozoic Ammonoidea; in Treatise on In v erteb rate P aleo n to lo g y , P art L, Mollusca 4; Geological Society of America and University of Kansas Press, Lawrence, 490 p. Behrendsen, O. 1891: Z ur G eologie des O stabhanges der a rg e n tin isc h e n C o rd ille re . I. Teil. Zeitschrift der Deutschen Geologischen Gesellschaft, v. 43, p. 369-420. Braga, J.C. 1983: Ammonites del Domerense de la Zona Subbetica (Cordilleras Breticas, Sur de Espana). Ph.D . thesis, University of Granada, Spain, 410 p. Braga, J.C. and Rivas, P. 1985: T h e M e d ite r r a n e a n Tropidoceras (Ammonitina) in the Betic Cordilleras. Eclogae Geologicae Helvetiae, v. 78, p. 567-605. Buckman, S.S. 1898: On the grouping of some divisions of so-called “ Jurassic” time. Q uarterly Journal of the Geological Society, v. 54, p. 442-462. 1909- Yorkshire Type Ammonites, I and II, and 1930: Type Ammonites, III and VII. Reprinted 1976, Wheldon and Wesley Ltd. and Verlag von Cramer, Herts, England.
Callomon, J.H. 1984: Biostratigraphy, chronostratigraphy and all that—again; in Proceedings of the Erlangen Symposium, O. Michelsen and A. Zeiss (eds.); International Subcommission on Jurassic stratigraphy, v. 3, p. 611-624. Cameron, B.E.B. and Tipper, H.W. 1985: Jurassic stratig rap h y of the Q ueen Charlotte Islands, British Colum bia. Geological Survey of Canada, Bulletin 365, 49 p. Cantaluppi, G. 1970: Le Hildoceratidae del Lias Medio delle regioni m editerranee. Memorie Della Societa Italiana di Scienze Naturali, v. 19, p. 1-46. Colera, I. R. 1978: Rivas, P., Sequeiros, L., and Valenzuela, Algunos M etaderoceras (Ammonitina) del Lias inferior de Almonacid de la Cuba (provincia de Zaragoza, Cordillera Iberica). Estudios Geologica, v. 34, p. 309-317. Coney, P.J., Jones, D.L., and Monger, J.W.H. 1980: Cordilleran suspect terranes. Nature, v. 288, p. 329-333. Dagis, A.A. 1974: Toarcian ammonites (Hildoceratidae) from the north of Siberia. Transactions of the Institute of Geology and Geophysics, U.S.S.R. Academy of Sciences, Siberian Branch, v. 99, 108 p. (In Russian.) Davidson, T. 1851: A m o nograph of the British fossil Brachiopoda: the oolitic and Liassic Brachiopoda. Palaeontographical Society Monograph, 64 p. Dean, W.T., Donovan, D.T., and Howarth, M.K. 1961: The Liassic ammonite zones and subzones of the northwest European province. British Museum (Natural History), Bulletin of Geology, v. 4, p. 435-505. Dommergues, J.-L. and Mouterde, R. 1978: Les faunes d ’am m onites du Carixien Inferieur et Moyen du gisement des C o tta r d s (C h e r). G e o b io s , v. 11, p. 345-365. 1981: Les acanthopleuroceratines Portugais et leurs relations avec les formes subboreales. Ciencias da Terra, no. 6, p. 71-100. 1982: Reynesocoeloceras praeincertum nov. sp. (Ammonitina, Carixien Moyen); Remarques sur Porigine du genre Reynesocoeloceras. Geobios, v. 15, p. 757-763. Dommergues, J.-L., Mouterde, R., and Rivas, P. 1984: Un faux Polymorphitine: D ubariceras nouveau genre d’Ammonitina du Carixien Mesogeen. Geobios, v. 17, p. 831-839. Donovan, D.T. 1967: The geographical distribution of Lower Jurassic ammonites in Europe and adjacent areas; in Aspects of Tethyan Biogeography, C.G . A dam s and D.V. Ager (eds.); Systematics Association Publication no. 7, p. 111-134. Donovan, D.T. and Forsey, G.F. 1973: Systematics of Lower Liassic Ammonitina. U niversity of K ansas P aleontology Contributions, Paper 64, 18 p. Donovan, D.T., Callomon, J.H., and Howarth, M.K. 1981: Classification of the Jurassic Ammonitina; in The Ammonoidea, M.R. House and J.R. Senior (eds.); Systematics Association Special Volume, no. 18, p. 101-155. Du Dresnay, R. 1963: Quelques ammonites de la partie inferieure du Pliensbachien (Carixien et Domerien pro parte) du jbel Bou-Rharraf (Haut Atlas Oriental). Notes du Service Geologique du Maroc, v. 23, n. 172, p. 141-164. Dubar, G. and Mouterde, R. 1978: Les formations a Ammonites du Lias Moyen dans le Haut Atlas de Midelt et du T a d la . N otes et M e m o irs, Service Geologique du Maroc, no. 274, 101 p. Dumortier, E. 1864- Etudes paleontologiques sur les depots 1874: jurassiques du Bassin du R hone, I, Infralias; II, Lias inferieur; III, Lias moyen; IV, Lias superieur. Paris.
Page 1 and 2: GEOLOGICAL SURVEY OF CANADA BULLETI
Page 3 and 4: PREFACE Study of the copious ammoni
Page 5 and 6: 12 12 13 14 21 25 26 35 56 9. Litho
Page 7 and 8: La faune d’ammonites est dominee
Page 9 and 10: INTRODUCTION The northern part of t
Page 11 and 12: Figure 4. Inferred stratigraphic re
Page 13 and 14: Figure 5. Distribution o f the fiv
Page 15 and 16: SOUTHWEST A Metres 2500 2000 1500 1
Page 17 and 18: SECTION 3 3 km southw est of Joan L
Page 19 and 20: Figure 12. Fossil localities and me
Page 21 and 22: D escription. Shell midvolute, whor
Page 23 and 24: fragments at which stage the whorl
Page 25 and 26: Material. A single, large whorl fra
Page 27 and 28: talkeetnaense is known from the Fre
Page 29 and 30: where they trend rursiradiately, th
Page 31 and 32: 40 35 30 25 20 15 10 35 30 25 20 15
Page 33 and 34: 1984 Dubariceras fre b o ld i Domme
Page 35 and 36: Family DACTYLIOCERATIDE Hyatt, 1867
Page 37 and 38: that bear only sporadic tubercles.
Page 39 and 40: Type species. Leptaleoceras leptum
Page 41 and 42: Discussion. Specimen is considered
Page 43 and 44: North America is poorly documented.
Page 45: Genus and species indet. Plate 16,
Page 49 and 50: Hallam, A. 1988: A re-evaluation of
Page 51 and 52: 1862: U b e r J u ra s s is c h e n
Page 53: Taylor, D.G., Smith, P.L., Laws, R.
Page 56 and 57: Locality Field no. GSC loc. no. GSC
Page 58 and 59: West end o f anticline The followin
Page 60 and 61: F F F F F F K K F K ? ? C K K F F F
Page 63: Figure 1. Camptonectes (Camptochlam
Page 67: Figures 1, 2. U ptonial sp. 1. Figu
Page 71: Figures 1-5. M etaderoceras talkeet
Page 75: Figures 1-4. M etaderoceras sp. cf.
Page 79: Figures 1-4. M iltoceras sp. 1. Fig
Page 83: Figures 1-7. Arieticeras sp. aff. A
Page 87: Figure 1. Genus and species indet.

PLIENSBACHIAN (LOWER JURASSIC) BIOSTRATIGRAPHY AND ...

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