Floristic composition and variation in late Paleocene to early Eocene floras in North America


Authors: Pigg KB, DeVore ML

Published in: Bulletin of Geosciences, volume 85, issue 1; pages: 135 - 154; Received 7 April 2009; Accepted in revised form 5 October 2009; Online 8 January 2010

Keywords: Almont/Beicegel Creek flora, Bighorn Basin, Eocene thermal maximum, Fort Union Formation, Golden Valley flora, Joffre Bridge, Paleocene/Eocene Transition,

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The late Paleocene and early Eocene megafossil floras in North America are found primarily in the Williston, Green River, Powder River, Bighorn, and Alberta Basins of the northern Rocky Mountains and Western Interior. A few rare sites occur in the Mississippi Embayment of the Southeast. In contrast to the abrupt floristic changes seen at the K/T boundary, these floras document a gradual transition in species turnover, or, in the case of the Bighorn Basin, a long-term decrease in taxonomic diversity. This gradual transition is also in marked contrast to the rapid speciation among mammals of the early Eocene. Both preservation, and ability to place these floras within a temporal scale, determine how useful they are in assessing floristic changes across the Paleocene-Eocene transition. In some regions such as the Bighorn Basin of Wyoming precise stratigraphic control has allowed for documentation of paleoclimate change at a highly resolved temporal scale. At others, such as the Almont flora of the Williston Basin in North Dakota, exceptional preservation has provided the basis for describing individual taxa with the precision necessary to better understand their evolutionary and biogeographical histories. This study examines well-known plant taxa in the late Paleocene and early Eocene in the context of their depositional settings and temporal and spatial distribution. Integration of paleoecological and taxonomic studies is critical to understanding the evolutionary and depositional history of early Paleocene vegetation of North America.


Arnold, C.A. 1955. A Tertiary Azolla from British Columbia. Contributions of the Museum of Paleontology of the University of Michigan 12, 37–45.

Barton, K.E., Howell, D.G. & Vigil, J.F. 2009. The North America tapestry of time and terrain. United States Geological Survey, Geologic Investigations Series I-2781, (accessed 27 October, 2009).

Basinger, J.F. 1981. The vegetative body of Metasequoia milleri from the Middle Eocene of southern British Columbia. Canadian Journal of Botany 59, 2379–2410.View article

Basinger, J.F. 1984. Seed cones of Metasequoia milleri from the middle Eocene of southern British Columbia. Canadian Journal of Botany 62(2), 281–289.View article

Basinger, J.F. & Rothwell, G.W. 1977. Anatomically preserved plants from the Middle Eocene (Allenby Formation) of British Columbia. Canadian Journal of Botany 54, 2379–2410.View article

Beck, R.A., Vondra, C.F., Filkins, J.E. & Olander, J.D. 1988. Syntectonic sedimentation and Laramide basement thrusting, Rocky Mountain foreland: timing and deformation, 465–487. In Schmidt, C.J. & Perry, W.J. (eds) Interaction of the Rocky Mountain Foreland and Cordilleran thrust belt. Geological Society of America Memoir 171.View article

Belt, E.S., Hartman, J.H., Diemer, J.A., Kroeger, T.J., Tibert, N.E. & Curran, H.A. 2004. Unconformities and age relationships, Tongue River and older members of the Fort Union Formation (Paleocene), western Williston Basin, U.S.A. Rocky Mountain Geology 39(2), 113–140.View article

Benedict, J.C., Pigg, K.B. & DeVore, M.L. 2008. Hamawilsonia boglei gen. et sp. nov. (Hamamelidaceae) from the Late Paleocene Almont flora of central North Dakota, USA. International Journal of Plant Sciences 169(5), 687–700.View article

Benedict, J.C., Taylor, W., Pigg, K.B. & DeVore, M.L. 2007. Late Paleocene seeds from Beicegel Creek (McKenzie County, North Dakota, USA) with affinities to the genus Spirematospermum Chandler (Zingiberales). Botany & Plant Biology 2007 (Chicago, July 2007), Abstract.

Broughton, P.I. 1979. Origin of coal basins by salt solution tectonics in western Canada. Ph.D. thesis, University of Cambridge, Cambridge U.K.

Brown, R.W. 1962. Paleocene floras of the Rocky Mountains and Great Plains. United States Geological Survey Professional Paper 375.

Department of the Interior, Washington, DC. Brown, T.M. & Kraus, M.J. 1981. Lower Eocene alluvial paleosols (Willwood Formation, Northwest Wyoming, U.S.A.) and their significance for paleoecology, paleoclima- tology and basin analysis. Palaeogeography, Palaeoclimatology, Palaeoecology 34, 1–30.View article

Bunker, B.J., Witzke, B.J., Watney, W.L. & Ludvigson, G.A. 1988. Phanerozoic history of the central midcontinent, United States, 243–260. In Sloss, L.L. (ed.) The Geology of North America, D-2. The Geological Society of America, Boulder.

Chandrasekharam, A. 1974. Megafossil flora from the Genesee locality, Alberta, Canada. Palaeontographica Abteilung B 147, 1–47.

Chen, I., Manchester, S.R. & Chen, Z. 2004. Anatomically preserved seeds of Nuphar (Nymphaeaceae) from the Early Eocene of Wutu, Shandong Province, China. American Journal of Botany 91(8), 1265–1272.View article

Clechenko, R.C., Kelly, D.C., Harrington, G.J. & Stiles, C.A. 2007. Terrestrial records of a regional weathering profile at the Paleocene-Eocene boundary in the Williston Basin of North Dakota. Geological Society of America Bulletin 119(3/4), 428–442.View article

Clyde, W.C., Hamzi, W., Finarelli, J.A., Wing, S.L., Schankler, D. & Chew, A. 2007. Basin-wide magnetostratigraphic framework for the Bighorn Basin, Wyoming. Geological Society of America Bulletin 119, 848–859.View article

Crane, P.R.,Manchester, S.R. & Dilcher, D.L. 1988. Morphology and phylogenetic significance of the angiosperm Platanites hebridicus from the Paleocene of Scotland. Palaeontology 31, 503–517.

Crane, P.R., Manchester, S.R. & Dilcher, D.L. 1990. A preliminary survey of fossil leaves and well-preserved reproductive structures from the Sentinel Butte Formation (Paleocene) near Almont, North Dakota. Fieldiana, Geology, New Series No. 20, Publication 1418, 1–63.

Crane, P.R., Manchester, S.R. & Dilcher, D.L. 1991. Reproductive and vegetative structure of Nordenskioldia (Trochodendraceae), a vesselless dicotyledon from the early Tertiary of the Northern Hemisphere. American Journal of Botany 78(10), 1311–1334.View article

Crane, P.R. & Stockey, R.A. 1985. Growth and reproductive biology of Joffrea speirsii gen. et sp. nov., a Cercidiphyllum- like plant from the Late Paleocene of Alberta, Canada. Canadian Journal of Botany 63, 340–364.View article

Crane, P.R. & Stockey, R.A. 1986. Morphology and development of pistillate inflorescences in extant and fossil Cercidiphyllaceae. Annals of the Missouri Botanical Garden 73(2), 382–393.View article

Crane, P.R. & Stockey, R.A. 1986. Betula leaves and reproductive structures from the Middle Eocene of British Columbia, Canada, Canadian Journal of Botany 65, 2490–2500.View article

Danehy, D.R., Wilf, P. & Little, S.A. 2007. Early Eocene macroflora from the Red Hot Truck Stop locality (Meridian, Mississippi, USA). Palaeontological Electronica 10(3), 17A, 1–31.

Davies-Vollum, K.S. & Wing, S.L. 1998. Sedimentological, taphonomic, and climatic aspects of Eocene swamp deposits (Willwood Formation, Bighorn Basin, Wyoming). Palaios 13(I), 28–40.View article

Decelles, T.C. 1994. Late Cretaceous-Paleocene synorogenic sedimentation and kindematic history of the Sevier thrust belt, northeast Utah and southwest Wyoming. Geological Society of America Bulletin 106, 32–56.View article

Demchuck, T., Cameron, A.R. & Hills, L.V. 1991. A re-examination of the Paskapoo Formation in the central Alberta Plains: the designation of three new members. Bulletin of Canadian Petroleum Geology 39, 270–282.

DeVore, M.L. & Pigg, K.B. 2008. Aquatic plants of the Eocene Republic, Washington flora and their significance to interpreting ancient lacustrine environments. Symposium: What Good are (Fossil) Plants Anyway? New Methods for Investigating Old Problems. Geological Society of America, Houston, October 2008, Paper No. 126-3, Abstracts.

DeVore, M.L., Sullivan, A.L. & Pigg, K.B. 2004. Monocots from the Late Paleocene of North Dakota. U.S.A. Botany 2004, Abstracts.

Doweld, A.B. 1998. Carpology, seed anatomy and taxonomic relationships of Tetracentron (Tetracentraceae) and Trochodendron (Trochodendaceae). Annals of Botany 82, 413–443.View article

Erickson, B.R. 1991. Flora and fauna of the Wannagan Creek Quarry: Late Paleocene of North America. Scientific Publications of the Science Museum of Minnesota New Series 7(3), 5–19.

Falder, A.B., Stockey, R.A. & Rothwell, G.W. 1999. In situ fossil seedlings of a Metasequoia-like taxodiaceous conifer from Paleocene river floodplain deposits of central Alberta, Canada. American Journal of Botany 86(6), 900–902.View article

Fischer, A.G. 1953. Geology of west central McKenzie County, North Dakota. North Dakota Geological Survey Report Inventory 11, 1 sheet.

Flores, R.M., Roberts, S.B. & Perry, W.J., Jr. 1994. Paleocene paleogeography of the Wind River, Bighorn, and Powder River basins, Wyoming, 1–16. In Flores, R.M., Mehring, K.T., Jones, R.W. & Beck, T.L. (eds) Organics and the Rockies Field Guide. Public Information Circular 33. Wyoming Geological State Survey.

Frank, M.C. & Bend, S.L. 2004. Peat-forming history of the ancestral Souris mire (Paleocene), Ravenscrag Formation, southern Saskatchewan, Canada. Canadian Journal of Earth Sciences 41, 307–322.View article

Gemmill, C.E. & Johnson, K.R. 1997. Paleoecology of a late Paleocene (Tiffanian) megaflora from the northern Great Divide Basin. Palaios 12(5), 439–448.View article

Gerhard, L.C., Anderson, S.B., Lefever, J.A. & Carlson, C.G. 1982. Geological development, origin, and energy mineral resources of Williston Basin, North Dakota. American Association of Petroleum Geologists 66(8), 989–1020.

Gingerich, P.D. 1983. Paleocene-Eocene faunal zones and a preliminary analysis of Laramide structural deformation in the Clark’s Fork Basin, Wyoming. Wyoming Geological Association Guidebook of the 34th Annual Field Conference, 185–195.

Graham, A. 1999. Late Cretaceous and Cenozoic history of North American vegetation. 350 pp. Oxford University Press, Oxford.

Hamilton, W.B. 1988. Laramide crustal shortening. Geological Society of America Memoir 171, 27–38.View article

Harrington, G.J. 2003. Wasatchian (Early Eocene) pollen floras from the Red Hot Truck Stop, Mississippi, USA. Palaeontology 46(4), 725–738.View article

Harrington, G.J. 2004. Structure of the North American vegetation gradient during the late Paleocene/early Eocene warm climate. Evolutionary Ecology Research 6, 33–48.

Harrington, G.J. 2008. Comparisons between Palaeocene- Eocene paratropical swamp and marginal marine pollen floras from Alabama and Mississippi, USA. Palaeontology 51(3), 611–622.View article

Harrington, G.J., Clechenko, E.R. & Kelly, D.C. 2005. Palynology and organic-carbon isotope ratios across a terrestrial Palaeocene/Eocene boundary section in the Williston Basin, North Dakota, USA. Palaeogeography, Palaeoclimatology, Palaeoecology 226(3–4), 214–232.View article

Harrington, G.J. & Jaramillo, C.A. 2007. Paratropical floral extinction in the Late Palaeocene-Early Eocene. Journal of the Geological Society of London 164, 323–332.View article

He, S.-A., Yin, G. & Pang, Z-J. 1997. Resources and prospects of Ginkgo biloba in China, 373–383. In Hori, T., Ridge, R.W., Tulecke, W., del Tredici, P., TremouillauxGuller, J. & Tobe, H. (eds) Ginkgo biloba: a global treasure. Springer, Tokyo.

Hickey, L.J. 1977. Stratigraphy and paleobotany of the Golden Valley Formation (Early Tertiary) of western North Dakota. The Geological Society of America Memoir 150, 1–181.

Hickey, L.J. 1980. Paleocene stratigraphy and flora of the of the Clark’s Fork Basin, 33–49. In Gingerich, P.D. (ed.) Early Cenozoic paleontology and stratigraphy of the Bighorn Basin, Wyoming. University of Michigan Museum of Paleontology, Volume 24.

Hickey, L.J. & Peterson, R.K. 1978. Zingiberopsis, a fossil genus of the ginger family from Late Cretaceous to Early Eocene sediments in Western Interior North America. Canadian Journal of Botany 56, 1136–1152.View article

Hoffman, G.L. 2002. Paleobotany and paleoecology of the Joffre Bridge Roadcut locality (Paleocene), Red Deer, Alberta. 2nd edition. M.Sc. thesis, University of Alberta, Edmonton, Alberta.

Hoffman, G.L. & Stockey, R.A. 1994. Sporophytes, megaspores, and massulae of Azolla stanleyi from the Paleocene Joffre Bridge locality, Alberta. Canadian Journal of Botany 72(3), 301–308.View article

Hoffman, G.L. & Stockey, R.A. 1997. Morphology and paleoecology of Ricciopsis speirsae sp. nov. (Ricciaceae), a fossil liverwort from the Paleocene Joffre Bridge locality, Alberta, Canada. Canadian Journal of Botany 75(8), 1375–1381.View article

Hoffman, G.L. & Stockey, R.A. 1999. Geological setting and paleobotany of the Joffre Bridge Roadcut fossil locality (Late Paleocene), Red Deer Valley, Alberta. Canadian Journal of Earth Science 3, 2073–2084.View article

Ingram, S.L. 1991. The Tuscahoma-Bashi section at Meridian, Mississippi: first notice of lowstand deposits above the Paleocene- Eocene TP2/TE1 sequence boundary. Mississippi Geology 11, 9–14.

Jacob, A.F. 1972. Depositional environments in parts of the Tongue River Formation, western North Dakota, 43–63. In Ting, F.T.C. (ed.) Depositional environments of the lignitebearing strata in western North Dakota. North Dakota Geological Survey Miscellaneous Series 50.

Johnson, K.R. 1992. Leaf-fossil evidence for extensive floral extinction at the Cretaceous-Tertiary boundary, North Dakota, USA. Cretaceous Research 13, 91–117.View article

Johnson, K.R. 2002. Megaflora of the Hell Creek and lower Fort Union Formations in the western Dakotas: Vegetational response to climate change, the Cretaceous-Tertiary boundary event, and rapid marine transgression, 329–392. In Hartman, J.H., Johnson, K.R. & Nichols, D.J. (eds) The Hell Creek Formation and the Cretaceous-Tertiary Boundary in the Northern Great Plains: An integrated continental record of the end of the Cretaceous. Special Paper 361. The Geological Society of America, Boulder.

Johnson, K.R. & Ellis, B. 2002. A tropical rainforest in Colorado 1.4 million years after the Cretaceous-Tertiary boundary. Science 296, 2379–2383.View article

Johnson, R.C. & Flores, R.M. 1998. Developmental geology of coalbed methane from shallow to deep in Rocky Mountain basins and in Cook Inlet–Matanuska Basin, Alaska, U.S.A. and Canada. International Journal of Coal Geology 35(1–4), 241–282.View article

Joy, K.W.,Willis, A.J. & Lacey, W.S. 1956. A rapid cellulose peel technique in palaeobotany. Annals of Botany (London), NS 20, 635–637.View article

Kvaček, Z., Manchester, S.R. & Guo, Shuang-xing 2001. Trifoliolate leaves of Platanus bella (Heer) comb. n. from the Paleocene of North America, Greenland, and Asia and their relationships among extinct and extant Platanaceae. International Journal of Plant Sciences 162(2), 441–458.

Kvaček, Z. & Manchester, S.R. 1999. Eostangeria Barthel (extinct Cycadales) from the Paleogene of western North America and Europe. International Journal of Plant Sciences 160(3), 621–629.View article

Kittle, A., DeVore, M.L., Wall, B. & Pigg, K. 2005. Acer fruits from the Paleocene of North Dakota. Georgia Academy of Sciences. Journal 63, 32.

Knowlton, F.H. 1893. Notes on a few fossil plants from the Fort Union group of Montana, with a description of one new species. United States National Museum Proceedings 16, 33–36.View article

Knowlton, F.H. 1919. A catalogue of the Mesozoic and Cenozoic plants of North America. United States Geological Survey Bulletin 696, 1–815.

Lesquereux, L. 1874. The lignitic formation and its fossil flora. United States Geological Survey of the Territories Annual Report (1893)7, 365–425.

Lesquereux, L. 1878. Contributions to the flora of the Western Territories. II. The Tertiary flora. Reports of the United States Geological Survey of the Territories 7, 1–366.

Manchester, S.R. 2001. Leaves and fruits of Aesculus (Sapindales) from the Paleocene of North America. International Journal of Plant Science 162(4), 985–998.View article

Manchester, S.R. 2002. Leaves and fruits of Davidia (Cornales) from the Paleocene of North America. Systematic Botany 27(2), 368–382.

Manchester, S.R. 2002. Morphology and phytogeographic history of Porosia Hickey in the Cretaceous and Paleocene of Asia and North America, and its distinction from Limnobiophyllum Krassilov, 180–181. In Akhmetiev, M.A., Doludenko, M.P., Herman, A.B. & Ignatiev, A.I. (eds) Special volume, dedicated to the memory of the Corresponding member of the USSR Academy of Sciences, Professor Vsevolod Andreevich Vakhrameev (to the 90th anniversary of his birth). Geological Institute Russian Academy of Sciences, Moscow.

Manchester, S.R., Akhmetiev, M.A. & Kodrul, T.M. 2002. Leaves and fruits of Celtis aspera (Newberry) comb. nov. (Celtidaceae) from the Paleocene of North America and eastern Asia. International Journal of Plant Sciences 163(5), 725–736.View article

Manchester, S.R. & Chen, Z.D. 1996. Palaeocarpinus aspinosa sp. nov. (Betulaceae) from the Paleocene of Wyoming, USA. International Journal of Plant Sciences 157(5), 644–655.View article

Manchester, S.R. & Chen, Z.D. 1998. A new genus of Coryloideae (Betulaceae) from the Paleocene of North America. International Journal of Plant Sciences 159(3), 522–532.View article

Manchester, S.R., Chen, Z.D., Lu, A.M., Uemura, K. 2009. Eastern Asian endemic seed plant genera and their paleogeographic history throughout the Northern Hemisphere. Journal of Systematics and Evolution 47 (1), 1-42.View article

Manchester, S.R., Crane, P.R. & Golovneva, L.B. 1999. An extinct genus with affinities to extant Davidia and Camptotheca (Cornales) from the Paleocene of North America and eastern Asia. International Journal of Plant Sciences 160(1), 188–207.View article

Manchester, S.R. & Dilcher, D.L. 1982. Pterocaryoid fruits (Juglandaceae) in the Paleogene of North America and their evolutionary and biogeographic significance. American Journal of Botany 69(2), 275–286.View article

Manchester, S.R. & Dilcher, D.L. 1997. Reproductive and vegetative morphology of Polyptera (Juglandaceae) from the Paleocene of Wyoming and Montana. American Journal of Botany 84(5), 649–663.View article

Manchester, S.R. & Hickey, L.J. 2007. Reproductive and vegetative organs of Browniea gen. n. (Nyssaceae) from the Paleocene of North America. International Journal of Plant Sciences 168(2), 229–249.View article

Manchester, S.R., Pigg, K.B. & Crane, P.R. 2004. Palaeocarpinus dakotensis sp. nov. (Betulaceae: Coryloideae) and associated staminate catkins, pollen and leaves from the Paleocene of North Dakota. International Journal of Plant Sciences 165(6), 1135–1148.View article

Manchester, S.R., & Zavada, M.S. 1987. Lygodium foliage with intact sorophores from the Eocene of Wyoming. Botanical Gazette 148 (3), 392-399.View article

Matthews, T., DeVore, M.L. & Pigg, K. 2006. Paleocene pteridophytes from the siliceous shales of western North Dakota. 23rd Annual Midcontinent Paleobotanical Colloquium, Florida Museum of Natural History, University of Florida, Gainesville, Florida, March 10–12, 2006, Abstract.

Matthews, T., Pigg, K.B., DeVore, M.L. & Rhode, J. 2007. Anatomically preserved Isoetes from the Paleocene of North Dakota: utility in ascertaining paleohabitat. Geological Society of America Abstracts with Programs 39(2), 29.

McIver, E.E. & Basinger, J.F. 1993. Flora of the Ravenscrag Formation (Paleocene), southwestern Saskatchewan, Canada. Palaeontographica Canadiana 10, 1–167.

Melchior, R.C. & Hall, J.W. 1983. Some megaspores and other small fossils from the Wannagan Creek site (Paleocene), North Dakota. Palynology 7, 133–145.View article

Newberry, J.S. 1868. Notes on the later extinct floras of North America with descriptions of some new species of fossil plants from the Cretaceous and Tertiary strata. Annals of the Lyceum of Natural History, New York 9, 1–76.

Nichols, D.J. & Johnson, K.R. 2008. Plants and the K-T boundary. 280 pp. Cambridge Paleobiology Series, Cambridge University Press, Cambridge.View article

Perry, W.J., Jr.,Weaver, J.N., Flores, R.M., Roberts, S.B. & Nichols, D.J. 1991. Sequential Laramide deformation in Montana and Wyoming. Geological Society of America Abstracts with Programs 23(4), 56.

Pigg, K.B. & DeVore, M.L. 2003. Paleocene fruits with affinities to Actinidiaceae from the Almont and Beicegel Creek floras of North Dakota. Botany 2003, Abstracts.

Pigg, K.B. & DeVore, M.L. 2005. Paleoactaea gen. nov. (Ranunculaceae) from the Paleogene of North Dakota and the London Clay. American Journal of Botany 92(10), 1650–1659.View article

Pigg, K.B., DeVore, M.L. & Brewer, M.A. 2005. Late Paleocene fruits similar to Ochna (Ochnaceae) from the Almont/Beicegel Creek floras, North Dakota, USA. Botany 2005, Austin, August 2005, Abstract.

Pigg, K.B., Devore, M.L. & Wojciechowski, M.F. 2008. Paleosecuridaca curtisii gen. et sp. nov., Securidaca-like samaras (Polygalaceae) from the Late Paleocene of North Dakota, USA and their significance to the divergence of families within the Fabales. International Journal of Plant Sciences 169, 1304–1313.View article

Pigg, K.B., Devore, M.L. & Wehr, W.C. 2006. Filicalean ferns from the Tertiary of western North America: Osmunda L. (Osmundaceae: Pteridophyta), Woodwardia Sm. (Blechnaceae: Pteridophyta), and onocleoid ferns (Filicales: Pteridophyta). Fern Gazette 17, 279–286.

Pigg, K.B.,Manchester, S.R. & DeVore, M.L. 2008. Fruits of Icacinaceae from the Late Paleocene of western North America. American Journal of Botany 95, 824–832.View article

Pigg, K.B. & Stockey, R.A. 1991. Platanaceous plants from the Paleocene of Alberta, Canada. Review of Palaeobotany and Palynology 70, 125–146.View article

Pigg, K.B., Stockey, R.A. & Maxwell, S.L. 1993. Paleomyrtinaea princetonensis gen. et sp. nov., permineralized myrtaceous fruits and seeds from the Princeton chert and related Myrtaceae from Almont, North Dakota. Canadian Journal of Botany 71(1), 1–9.View article

Rich, F.J. 1979. The origin and development of tree islands in the Okefenokee Swamp, as determined by peat petrography and pollen stratigraphy. Ph.D. thesis, The Pennsylvania State University, University Park.

Roehler, H.W. 1985. Geologic map of the Kinney Rim 30 × 60 minute quadrangle, Wyoming and Colorado. U.S. Geological Survey Miscellaneous Investigations Map I-1615, 1 sheet, scale: 1 : 100 000.

Roehler, H.W. 1993. Eocene climates, depositional environments, and geography, greater Green River Basin, Wyoming, Utah, and Colorado. United States Geological Survey Professional Paper 1506F, 1–74.

Rothwell, G.W. & Basinger, J.F. 1979. Metasequoia milleri n. sp., anatomically preserved pollen cones from the middle Eocene (Allenby Formation) of British Columbia. Canadian Journal of Botany 57(8), 958–970.View article

Rothwell, G.W. & Stockey, R.A. 1989. Fossil Ophioglossales in the Paleocene of western North America. American Journal of Botany 76(5), 637–644.View article

Rothwell, G.W. & Stockey, R.A. 1991. Onoclea sensibilis in the Paleocene of North America, a dramatic example of structural and ecological stasis. Review of Palaeobotany and Palynology 70(1–2), 113–124.View article

Royer, D.L., Hickey, L. J. & Wing, S.L. 2003. Ecological conservatism in the “living fossil” Ginkgo. Paleobiology 29(1), 84–104.View article

Saskatchewan Geological Survey (S.G.S.). 1994. Geology and mineral resources of Saskatchewan. Saskatchewan Energy and Mines, Miscellaneous Report 94-6.

Stockey, R.A. & Crane, P.R. 1983. In situ Cercidiphyllumlike seedlings from the Paleocene of Alberta, Canada. American Journal of Botany 70(12), 1564–1568.View article

Stockey, R.A., Rothwell, G.W. & Falder, A.B. 2001. Diversity among taxodiaceous conifers: Metasequoia foxii sp. nov. from the Paleocene of central Alberta, Canada. International Journal of Plant Sciences 162(1), 221–234.View article

Stockey, R.A., Hoffman, G.L. & Rothwell, G.W. 1997. The fossil monocot Limnobiophyllum scutatum: resolving the phylogeny of Lemnaceae. American Journal of Botany 84(3), 355–368.View article

Stockey, R.A., Lantz, T.C. & Rothwell, G.W. 2006. Speirseopteris orbiculata gen. et sp. nov. (Thelypteridaceae), a derived fossil filicalean from the Paleocene of western North America. International Journal of Plant Sciences 167(3), 729–736.View article

Sun, F. & Stockey, R.A. 1992. A new species of Palaeocarpinus Crane based on infructescences, fruits, seeds, staminate cones and leaves from the Paleocene of Alberta, Canada. International Journal of Plant Sciences 153(1), 136–146.View article

Taylor,W. 2007. Cyclocarya and its significance to the diversification of Juglandaceae. Botany & Plant Biology 2007, Abstracts.

Taylor, W., DeVore, M.L. & Pigg, K.B. 2006. Susiea newsalemae, gen. et sp. nov. (Nymphaeaceae): Euryale-like seeds from the Late Paleocene Almont flora, North Dakota, USA. International Journal of Plant Sciences 167(6), 1271–1278.View article

Tiffney, B.H.&Haggard, K.K. 1996. Fruits of Mastixioideae (Cornaceae) from the Paleogene of western North America. Review of Palaeobotany and Palynology 92(6), 29–54.View article

Tikoff, B. & Mason, J. 2001. Lithospheric buckling of the Laramide foreland during the Late Cretaceous and Paleogene. Rocky Mountain Geology 36(1), 13–35.View article

Ting, F.T.C. 1972. Petrified peat from a Paleocene lignite in North Dakota. Science 177, 165–166.View article

Vavrek, M.J. 2002. Palaeobotany and palaeoecology of the Munce’s Hill locality near Red Deer, Alberta. B.Sc. thesis, University of Alberta, Edmonton. Ward, L.F. 1885. Synopsis of the flora of the Laramie group. United States Geological Survey 6th Annual Report, 399–557.

Wilf, P. 2000. Late Paleocene–early Eocene climate changes in southwestern Wyoming: Paleobotanical analysis. Geological Society of America Bulletin 112, 292–307.View article

Wing, S.L. §1984§. Relation of paleovegetation to geometry and cyclicity of some fluvial carbonaceous deposits. Journal of Sedimentary Petrology 54, 52–66.

Wing, S.L. §1997§. Global warming and plant species richness: a case study of the Paleocene/Eocene boundary, 161–185. In Reaka-Kudla, M.L., Wilson, D.E. & Wilson, E.O. (eds) Biodiversity II. Understanding and protecting our biological resources. Joseph Henry Press, Washington, D.C.

Wing, S.L. §1998§. Tertiary vegetation of North America as a context for mammalian evolution. In Janis, C.M., Scott, K.M.& Jacobs, L.L. (eds) Evolution of Tertiary mammals of North America. Volume 1: Terrestrial carnivores, ungulates, and ungulatelike mammals. Cambridge University Press, Cambridge, UK.

Wing, S.L. §2000§. Cool, warm, cool, warm – climate oscillation and floral change during the Paleocene-Eocene boundary interval. GFF 122(1), 182–183.View article

Wing, S.L., Alroy, J. & Hickey, L.J. §1995§. Plant and mammal diversity in the Paleocene to Early Eocene of the Bighorn Basin. Palaeogeography, Palaeoclimatology, Palaeoecology 115(1–4), 117–155.View article

Wing, S.L., Bao, H. & Koch, P.L. §2000§. An early Eocene cooling period? Evidence for continental cooling during the warmest parts of the Cenozoic, 197–237. In Huber, B.T., MacLeod, K.G.&Wing, S.L. (eds) Warm climates in earth history. Cambridge University Press, Cambridge, UK.View article

Wolfe, J.A. §1987§. An overview of the origins of the modern vegetation and flora of the northern Rocky Mountains. Annals of the Missouri Botanical Garden 74(4), 785–803.View article

Wolfe, J.A. & Upchurch, G.R., Jr. §1987§. Leaf assemblages across the Cretaceous-Tertiary boundary in the Raton Basin, New Mexico and Colorado. Proceedings of the National Academy of Science 84, 5096–5100.View article

Wood, H.E., Chaney, R.W., Clark, J., Colbert, E.H., Jepsen, G.L., Reeside, J.J.R. & Stock, C. §1941§. Nomenclature and correlation of the North America continental Tertiary. Geological Society of America Special Paper 162, 1–91.

Woodburne, M.O. 2004. Late Cretaceous Cenozoic mammals of North America. 2nd edition. Columbia University Press, New York.View article

Xiang, (J.) Q.-Y., Shui, Y. & Murrell, Z. §2003§. Cornus eydeana (Cornaceae), a new cornelian cherry from China – Notes on systematics and evolution. Systematic Botany 28(4), 757–764.