Hostname: page-component-cd9895bd7-jn8rn Total loading time: 0 Render date: 2024-12-26T18:46:53.489Z Has data issue: false hasContentIssue false
  • English
  • Français

North American mammalian diversity and Eocene–Oligocene extinctions

Published online by Cambridge University Press:  08 February 2016

Donald R. Prothero
Donald R. Prothero*
Affiliation:
Department of Geology, Occidental College, Los Angeles, California 90041
Get access Rights & Permissions [Opens in a new window]

Abstract

Diversity and faunal turnover of North American land mammals are calibrated against the magnetic polarity time scale for million-year intervals for the latest Eocene through late Oligocene. A major, gradual Late Eocene decline in diversity, caused mostly by an extended period of extinction of archaic forms, seems to be related to the worldwide crisis known as the “Terminal Eocene Event.” Along with other evidence of gradual changes in deep-sea microfossils, this evidence argues against a catastrophic explanation for late Eocene extinctions.

Faunal stability characterized the rest of the Oligocene except for a wave of extinctions in the mid-Oligocene (Chadronian-Orellan boundary, about 32.4 ma). This mid-Oligocene event is sudden and severe, occurring in less than 200,000 yr, based on estimates from sedimentation rates calibrated from magnetic polarity interval boundaries. The mid-Oligocene event is found in many paleoclimatic records, but not in all of them. It may be related to the completion of the Circum-Antarctic Current and to increased mid-Oligocene glaciation.

Type
Research Article
Information
Paleobiology , Volume 11 , Issue 4 , Fall 1985 , pp. 389 - 405
Copyright
Copyright © The Paleontological Society 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Literature Cited

Alvarez, W., Asaro, F., Michel, H. V., and Alvarez, L. W. 1982. Iridium anomaly approximately synchronous with terminal Eocene extinctions. Science. 216:886–888.CrossRefGoogle ScholarPubMed
Armentrout, J. M. 1981. Correlation and ages of Cenozoic chronostratigraphic units in Oregon and Washington. Geol. Soc. Am. Spec. Pap. 184:137–148.Google Scholar
Asaro, F., Alvarez, L. W., Alvarez, W., and Michel, H. V. 1982. Geochemical anomalies near the Eocene/Oligocene and Permian/Triassic boundaries. Geol. Soc. Am. Spec. Pap. 190:517–528.Google Scholar
Axelrod, D. W. 1981. Role of volcanism in climate and evolution. Geol. Soc. Am. Spec. Pap. 185.Google Scholar
Barker, P. F. and Burrell, J. 1977. The opening of the Drake Passage. Mar. Geol. 25:15–34.CrossRefGoogle Scholar
Barnosky, A. D. 1981. A skeleton of Mesoscalops (Mammalia: Insectivora) from the Miocene Deep River Formation, Montana, and a review of the proscalopid moles: evolutionary, functional, and stratigraphic relationships. J. Vert. Paleontol. 1:285–339.CrossRefGoogle Scholar
Berger, W. H. 1982. Climate steps in ocean history—lessons from the Pleistocene. Pp. 43–54. In: Berger, W. H. and Crowell, J. C., eds. Climate in Earth History. Studies in Geophysics. National Acad. Press; Washington, DC.Google Scholar
Berggren, W. A. 1982. Role of ocean gateways in climate change. Pp. 118–125. In: Berger, W. H. and Crowell, J. C., eds. Climate in Earth History. Studies in Geophysics. National Acad. Press; Washington, DC.Google Scholar
Berggren, W. A., Kent, D. V., and Flynn, J. J. 1985. Paleogene geochronology and chronostratigraphy. In: Snelling, N. J., ed. Geochronology and the Geological Record. Geol. Soc. Lond. Spec. Pap.Google Scholar
Bjork, P. R. 1975. Observations on the morphology of the hedgehog genus Proterix (Insectivora: Erinaceidae). Univ. Mich. Pap. Paleontol. 12:81–88.Google Scholar
Black, C. C. 1978. Paleontology and geology of the Badwater Creek area, central Wyoming. Part 14. The artiodactyls. Ann. Carnegie Mus. 47:223–259.CrossRefGoogle Scholar
Black, C. C. and Dawson, M. R. 1966. A review of Late Eocene mammalian faunas from North America. Am. J. Sci. 264:321–349.CrossRefGoogle Scholar
Brunet, M. 1977. Les mammiferes et le probleme de la limite Eocene-Oligocene en Europe. Geobios Mem. Spec. 1:11–27.CrossRefGoogle Scholar
Brunet, M. 1979. Les grands Mammiferes chefs de file de l'immigration oligocene et le probleme de la limite Eocene-Oligocene en Europe. Fondation Singer-Polignac; Paris. 223 pp.Google Scholar
Cavelier, C. 1979. La limite Eocene-Oligocene en Europe occidentale. Mem. Sci. Geol. 54:280 pp.Google Scholar
Cavelier, C., Chateauneuf, J.-J., Pomerol, C., Rabussier, D., Renard, M., and Vergnaud-Grazzini, C. 1981. The geological events at the Eocene/Oligocene Boundary. Palaeogeogr., Palaeoclimatol., Palaeoecol. 36:223–248.CrossRefGoogle Scholar
Clark, J., Beerbower, J. R., and Kietzke, K. K. 1967. Oligocene sedimentation, stratigraphy, paleoecology, and paleoclimatology in the Big Badlands of South Dakota. Fieldiana: Geol. Mem. 5:158 pp.Google Scholar
Clemens, W. A. Jr. 1964. Records of the fossil mammal Sinclairella, Family Apatemyidae, from the Chadronian and Orellan. Univ. Kansas Mus. Nat. Hist. Publ. 14:483–491.Google Scholar
Collinson, M. E., Fowler, K., and Boulter, M. C. 1981. Floristic changes indicate a cooling climate in the Eocene of southern England. Nature. 291:315–317.CrossRefGoogle Scholar
Cook, H. J. 1954. A remarkable new mammal from the Lower Chadron of Nebraska. Am. Midland Nat. 52:388–391.CrossRefGoogle Scholar
Corliss, B. 1981. Deep-sea benthonic foraminiferal faunal turnover near the Eocene/Oligocene Boundary. Mar. Micropaleontol. 6:367–384.CrossRefGoogle Scholar
Corliss, B. H., Aubry, M.-P., Berggren, W. A., Fenner, J. M., Keigwin, L. D. Jr., and Keller, G. 1984. The Eocene/Oligocene Boundary event in the deep sea. Science. 226:806–810.CrossRefGoogle ScholarPubMed
Crochet, J. Y., Hartenberger, J. L., Rage, J. C., Remy, J. A., Sige, B., Sudre, J., and Vianey-Liaud, M. 1982. Les nouvelles faunes des vertebres anterieures a la “Grande Coupure” decouvertes dans les phosphorites du Quercy. Bull. Mus. Natl. Hist. Nat. Paris. 3:245–260.Google Scholar
Dalrymple, G. B. 1979. Critical tables for conversion of K-Ar ages from old to new constants. Geology. 7:558–560.2.0.CO;2>CrossRefGoogle Scholar
Davis, M., Hut, P., and Muller, R. A. 1984. Extinction of species by periodic comet showers. Nature. 308:715–717.CrossRefGoogle Scholar
Dawson, M. R. 1980. Paleontology and geology of the Badwater Creek area, central Wyoming. Part 20. The Late Eocene Creodonta and Carnivora. Ann. Carnegie Mus. 49:79–91.CrossRefGoogle Scholar
Edwards, P. R. 1976. The subfamily Leptochoerinae (Artiodactyla, Dichobunidae) of North America (Oligocene). Contr. Geol. Univ. Wyoming. 14:99–113.Google Scholar
Emry, R. J. 1973. Stratigraphy and preliminary biostratigraphy of the Flagstaff Rim area, Natrona County, Wyoming. Smithsonian Contr. Paleobiology. 18:1–43.Google Scholar
Emry, R. J. 1978. A new hypertragulid (Mammalia, Ruminantia) from the early Chadronian of Wyoming and Texas. J. Paleontol. 52:1004–1014.Google Scholar
Emry, R. J. 1981. Additions to the mammalian fauna of the type Duchesnean, with comments on the status of the Duchesnean “Age.” J. Paleontol. 55:563–570.Google Scholar
Emry, R. J., Bjork, P. R., and Russell, L. S. 1986. The Chadronian, Orellan, and Whitneyan land mammal ages. In: Woodburne, M. O., ed. Cenozoic Mammals: their Temporal Record, Biostratigraphy, and Biochronology. Univ. Calif. Press; Berkeley.Google Scholar
Emry, R. J. and Hunt, R. M. Jr. 1980. Maxillary dentition and new records of Daphoenictis, an Oligocene amphicyonid carnivore. J. Mammal. 61:720–723.CrossRefGoogle Scholar
Emry, R. J. and Storer, J. R. 1981. The hornless protoceratid Pseudoprotoceras (Tylopoda: Artiodactyla) in the early Oligocene of Saskatchewan and Wyoming. J. Vert. Paleontol. 1:101–110.CrossRefGoogle Scholar
Fischer, A. G. and Arthur, M. A. 1977. Secular variations in the pelagic realm. Soc. Econ. Paleontol. Min. Spec. Publ. 25:19–50.Google Scholar
Frakes, L. A. 1979. Climates Through Geologic Time. 310 pp. Elsevier; Amsterdam.Google Scholar
Ganapathy, R. 1982. Evidence for a major meteorite impact on the earth 34 million years ago: implications for Eocene extinctions. Science. 216:885–886.CrossRefGoogle Scholar
Gawne, C. E. 1968. The genus Proterix (Insectivora, Erinaceidae) of the upper Oligocene of North America. Am. Mus. Novitates. 2315:1–26.Google Scholar
Gawne, C. E. 1978. Leporids (Lagomorpha, Mammalia) from the Chadronian (Oligocene) deposits of Flagstaff Rim, Wyoming. J. Paleontol. 52:1103–1118.Google Scholar
Glass, B. P. and Crosbie, J. R. 1982. Age of the Eocene/Oligocene boundary based on extrapolation from the North American microtektite layer. Am. Assoc. Petrol. Geol. Bull. 66:471–476.Google Scholar
Green, M. and Martin, J. E. 1976. Peratherium (Marsupialia: Didelphidae) from the Oligocene and Miocene of South Dakota. Pp. 155–168. In: Churcher, C. S., ed. Athlon: Essays on palaeontology in honour of Loris Shano Russell. Roy. Ontario Mus. Misc. Publ.; Toronto.Google Scholar
Gregory, J. T. 1971. Speculations on the significance of fossil vertebrates for the antiquity of the Great Plains in North America. Abh. Hessisches Landesamtes für Bodenforsch. (Heinz Tobien Festschrift). Pp. 64–72.Google Scholar
Hallam, A. 1984. The causes of mass extinction. Nature. 308:686–687.CrossRefGoogle Scholar
Hansen, T. A. 1984. Bivalve extinction patterns in the Late Eocene and Oligocene of the Gulf Coast: relationship to temperature drops and changes in shelf area. Geol. Soc. Am. Abstr. Prog. 16(6):529.Google Scholar
Haq, B. U. and Lohmann, G. P. 1976. Early Cenozoic calcareous nannoplankton biogeography of the Atlantic Ocean. Mar. Micropaleontol. 1:119–194.CrossRefGoogle Scholar
Harper, C. W. Jr. 1975. Standing diversity of fossil groups in successive intervals of geologic time: a new measure. J. Paleontol. 49:752–757.Google Scholar
Heissig, K. 1979. Die hypothetische Rolle Südosteuropas bei den Säugetierwanderungen im Eozän und Oligozän. N. Jb. Geol. Paläontol. Monat. 2:83–96.Google Scholar
Hutchinson, J. H. 1982. Turtle, crocodilian, and champsosaur diversity changes in the Cenozoic of the north-central region of the western United States. Palaeogeogr., Palaeoclimat., Palaeoecol. 37:149–164.CrossRefGoogle Scholar
Janacek, T. R. and Rea, D. K. 1983. Eolian depositon in the northeast Pacific Ocean: Cenozoic history of atmospheric circulation. Geol. Soc. Am. Bull. 94:730–738.2.0.CO;2>CrossRefGoogle Scholar
Keigwin, L. and Keller, G. 1984. Middle Oligocene cooling from Equatorial Pacific DSDP Site 77B. Geology. 12:16–19.2.0.CO;2>CrossRefGoogle Scholar
Keller, G. 1983a. Paleoclimatic analyses of middle Eocene through Oligocene planktic foraminiferal faunas. Palaeogeogr., Palaeoclimat., Palaeoecol. 43:73–94.CrossRefGoogle Scholar
Keller, G. 1983b. Biochronology and paleoclimatic implications of middle Eocene to Oligocene planktic foraminiferal faunas. Mar. Micropaleontol. 7:463–486.CrossRefGoogle Scholar
Keller, G., D'Hondt, S., and Vallier, T. L. 1983a. Multiple microtektite horizons in Upper Eocene marine sediments: no evidence for mass extinctions. Science. 221:150–153.CrossRefGoogle ScholarPubMed
Keller, G., D'Hondt, S., and Vallier, T. L. 1983b. Multiple microtektite horizons in Upper Eocene marine sediments: reply to B. Glass. Science. 224:309–310.Google Scholar
Kennett, J. P. 1977. Cenozoic evolution of Antarctic glaciation, the Circum-Antarctic Ocean, and their impact on global paleoceanography. J. Geophys. Res. 82:3843–3859.CrossRefGoogle Scholar
Kennett, J. P. 1981. Marine Geology. 813 pp. Prentice-Hall, Inc.; Englewood Cliffs, NJ.Google Scholar
Kerr, R. A. 1984. Vail's sea-level curves aren't going away. Science. 226:677–678.CrossRefGoogle Scholar
Kitchell, J. A. and Pena, D. 1984. Periodicity of extinctions in the geologic past: deterministic versus stochastic explanations. Science. 226:689–692.CrossRefGoogle ScholarPubMed
Korth, W. W. 1981a. Metadjidaumo (Eomyidae, Rodentia) from Colorado and Wyoming. J. Paleontol. 55:598–602.Google Scholar
Korth, W. W. 1981b. New Oligocene rodents from western North America. Ann. Carnegie Mus. 50:289–318.CrossRefGoogle Scholar
Krishtalka, L. and Stucky, R. K. 1983. Paleocene and Eocene marsupials of North America. Ann. Carnegie Mus. Nat. Hist. 52:229–263.CrossRefGoogle Scholar
Krishtalka, L., Emry, R. J., Storer, J. E., and Sutton, J. F. 1982. Oligocene multituberculates (Mammalia: Allotheria): youngest known record. J. Paleontol. 56:791–794.Google Scholar
Krishtalka, L. and Setogouchi, T. 1977. Paleontology and geology of the Badwater Creek area, central Wyoming. Part 13. The Late Eocene Insectivora and Dermoptera. Ann. Carnegie Mus. 46:71–99.CrossRefGoogle Scholar
Kyte, F. T. 1984. Cenozoic iridium sedimentation: death of the nemesis? Geol. Soc. Am. Abstr. Prog. 16(6):567.Google Scholar
LaBrecque, J. L., Kent, D. V., and Cande, S. C. 1977. Revised magnetic polarity timescale for late Cretaceous and Cenozoic time. Geology. 5:330–335.2.0.CO;2>CrossRefGoogle Scholar
Lander, E. B. 1977. A review of the Oreodonta (Mammalia, Artiodactyla). Unpubl. doct. diss., Univ. Calif., Berkeley. 178 pp.Google Scholar
Lillegraven, J. A. 1972. Ordinal and familial diversity of Cenozoic mammals. Taxon. 21:261–274.CrossRefGoogle Scholar
Lillegraven, J. A., McKenna, M. C., and Krishtalka, L. 1981. Evolutionary relationships of middle Eocene and younger species of Centetodon (Mammalia, Insectivora, Geolabididae) with a description of the dentition of Ankylodon (Adapisoricidae). Univ. Wyoming Publ. 45:1–115.Google Scholar
Lowrie, W., Alvarez, W., Napoleone, G., Perch-Nielsen, K., Premoli-Silva, I., and Toumarkine, M. 1982. Paleogene magnetic stratigraphy in Umbrian pelagic rocks: the Contessa sections, Gubbio. Geol. Soc. Am. Bull. 93:414–432.2.0.CO;2>CrossRefGoogle Scholar
Macdonald, J. R. 1956. The North American anthracotheres. J. Paleontol. 30:615–645.Google Scholar
Macdonald, J. R. 1963. The Miocene faunas from the Wounded Knee area of western South Dakota. Am. Mus. Nat. Hist. Bull. 125:139–238.Google Scholar
Macdonald, J. R. 1970. Review of the Miocene Knee faunas of southwestern South Dakota. Bull. L.A. County Mus. Nat. Hist. Sci. 8:1–82.Google Scholar
Marshall, L. G. 1981. The Great American Interchange—an invasion-induced crisis for South American mammals. Pp. 133–230. In: Nitecki, M. H., ed. Biotic Crises in Ecological and Evolutionary Time. Academic Press; New York.CrossRefGoogle Scholar
Martin, L. D. 1980. The early evolution of the Cricetidae of North America. Univ. Kansas Paleontol. Contr. 102:1–42.Google Scholar
McKenna, M. C. 1975. Fossil mammals and Early Eocene North Atlantic land continuity. Ann. Missouri Bot. Gard. 62:335–353.CrossRefGoogle Scholar
McKenna, M. C. 1983. Holarctic landmass rearrangement, cosmic events, and Cenozoic terrestrial organisms. Ann. Missouri Bot. Gard. 70:459–489.CrossRefGoogle Scholar
Mellett, J. S. 1977. Paleobiology of North American Hyaenodon (Mammalia, Creodonta). Contr. Vert. Evol. 1:1–134.Google Scholar
Miller, K. G. and Fairbanks, R. G. 1983. Evidence for Oligocene-Middle Miocene abyssal circulation changes in the western North Atlantic. Nature. 306:250–252.CrossRefGoogle Scholar
Miller, K. G., Mountain, G. S., and Tucholke, B. E. 1985. Oligocene glacio-eustasy and erosion on the margins of the North Atlantic. Geology 13:10–13.2.0.CO;2>CrossRefGoogle Scholar
Murphy, M. G. and Kennett, J. P. 1985. Development of latitudinal thermal gradients during the Oligocene: oxygen isotopic evidence from the southwest Pacific. Initial Reports of the Deep Sea Drilling Project 90 (in press).Google Scholar
Norris, G. 1982. Spore-pollen evidence of Oligocene high-latitude cool climate episodes in northern Canada. Nature. 297:387–388.CrossRefGoogle Scholar
Ostrander, G., Jones, C. A., and Cape, R. 1979. The occurrence of a multituberculate in the Lower Oligocene Chadron Formation of northwest Nebraska. Geol. Soc. Am. Abstr. Prog. 11(6):299.Google Scholar
Patton, T. H. and Taylor, B. E. 1973. The Protoceratinae (Mammalia, Tylopoda, Protoceratidae) and the systematics of the Protoceratidae. Am. Mus. Nat. Hist. Bull. 150:347–414.Google Scholar
Percival, S. F. Jr. 1984. Late Cretaceous to Pleistocene calcareous nannofossils from the South Atlantic, DSDP Leg 73. Init. Repts. Deep-Sea Drilling Proj. 73:391–424.Google Scholar
Poag, C. W. and Schlee, J. S. 1984. Depositional sequences and stratigraphic gaps on the submerged United States Atlantic margin. Am. Assoc. Petrol. Geol. Mem. 36:165–182.Google Scholar
Poore, R. Z., Tauxe, L., Percival, S. F. Jr., and LaBrecque, J. L. 1982. Late Eocene-Oligocene magnetostratigraphy and biostratigraphy at South Atlantic DSDP Site 522. Geology. 10:508–511.2.0.CO;2>CrossRefGoogle Scholar
Poore, R. Z. and others. 1984. Late Cretaceous to Cenozoic magnetostratigraphic and biostratigraphic correlations of the South Atlantic Ocean: DSDP Leg 73. Init. Repts. Deep-Sea Drilling Proj. 73:645–656.Google Scholar
Prothero, D. R. 1982. Medial Oligocene magnetostratigraphy and mammalian biostratigraphy: testing the isochroneity of mammalian biostratigraphic events. Unpubl. doct. diss., Columbia Univ., New York. 284 pp.Google Scholar
Prothero, D. R. 1985. Chadronian (Early Oligocene) magnetostratigraphy of eastern Wyoming: implications for the age of the Eocene-Oligocene boundary. J. Geol. 93:555–565.CrossRefGoogle Scholar
Prothero, D. R., Denham, C. R., and Farmer, H. G. 1982. Oligocene calibration of the magnetic polarity timescale. Geology. 10:650–653.2.0.CO;2>CrossRefGoogle Scholar
Prothero, D. R., Denham, C. R., and Farmer, H. G. 1983. Magnetostratigraphy of the White River Group and its implications for Oligocene geochronology. Palaeogeogr., Palaeoclimatol., Palaeoecol. 42:151–166.CrossRefGoogle Scholar
Prothero, D. R. and Shubin, N. 1983. Tempo and mode of speciation in Oligocene mammals. Geol. Soc. Am. Abstr. Prog. 16(6):665.Google Scholar
Radinsky, L. 1963. Origin and early evolution of North American Tapiroidea. Bull. Peabody Mus. Nat. Hist., 17:1–106.Google Scholar
Radinsky, L. 1967. A review of the rhincerotoid family Hyracodontidae (Perissodactyla). Am. Mus. Nat. Hist. Bull. 136:1–45.Google Scholar
Rampino, M. R. and Stothers, R. B. 1984. Terrestrial mass extinctions, cometary impacts and the Sun's motion perpendicular to the galactic plane. Nature. 308:709–712.CrossRefGoogle Scholar
Raup, D. M. and Marshall, L. G. 1980. Variation between groups in evolutionary rates: a statistical test of significance. Paleobiology. 6:9–23.CrossRefGoogle Scholar
Raup, D. M. and Sepkoski, J. J. Jr. 1984. Periodicity of extinctions in the geologic past. Proc. Natl. Acad. Sci. USA. 81:801–805.CrossRefGoogle ScholarPubMed
Repenning, C. A. 1967. Subfamilies and genera of the Soricidae. U.S. Geol. Surv. Prof. Pap. 565:1–74.Google Scholar
Retallack, G. J. 1983. Late Eocene and Oligocene paleosols from Badlands National Park, South Dakota. Geol. Soc. Am. Spec. Pap. 193:1–82.Google Scholar
Rose, K. D. 1978. A new Paleocene epocotheriid (Mammalia), with comments on the Palaeonodonta. J. Paleontol. 52:658–674.Google Scholar
Russell, D. A. 1960. A review of the Oligocene insectivore Micropternodus borealis. J. Paleontol. 34:940–949.Google Scholar
Russell, L. S. 1978. Tertiary mammals of Saskatchewan. Part IV. The Oligocene Anthracotheres. Life Sci. Contr. Roy. Ont. Mus. 115:1–16.Google Scholar
Savage, D. E. and Russell, D. E. 1983. Mammalian paleofaunas of the world. Addison-Wesley Publ.; Reading, Mass.Google Scholar
Savin, S. M. 1977. The history of the earth's surface temperature during the past 100 million years. Ann. Rev. Earth Planet. Sci. 5:319–355.CrossRefGoogle Scholar
Schwartz, R. D. and James, P. B. 1984. Periodic mass extinctions and the Sun's oscillation about the galactic plane. Nature. 308:712–713.CrossRefGoogle Scholar
Setogouchi, T. 1978. Paleontology and geology of the Badwater Creek area, central Wyoming. Part 16. The Cedar Ridge local fauna (late Oligocene). Bull. Carnegie Mus. Nat. Hist. 9:1–61.CrossRefGoogle Scholar
Simpson, G. G. 1947. Holarctic mammalian faunas and continental relationships during the Cenozoic. Geol. Soc. Am. Bull. 58:613–688.CrossRefGoogle Scholar
Snyder, S. W., Muller, C., and Miller, K. G. 1984. Eocene-Oligocene boundary: biostratigraphic recognition and gradual paleoceanographic change at DSDP Site 549. Geology. 12:112–115.2.0.CO;2>CrossRefGoogle Scholar
Stanley, S. M. 1984a. Temperature and biotic crises in the marine realm. Geology. 12:205–208.2.0.CO;2>CrossRefGoogle Scholar
Stanley, S. M. 1984b. Marine mass extinctions: a dominant role for temperatures. Pp. 69–118. In: Nitecki, M. H., ed. Extinctions. Univ. Chicago Press; Chicago.Google Scholar
Stehlin, H. G. 1909. Remarques sur les faunules de Mammiferes des couches eocenes et oligocenes du Bassin de Paris. Bull. Soc. Geol. France. 9:488–520.Google Scholar
Storer, J. E. 1981. Leptomerycid Artiodactyla of the Calf Creek Local Fauna. Nat. Hist. Contr. Saskatchewan Mus. Nat. Hist. 3:1–32.Google Scholar
Talwani, M. and Eldholm, O. 1977. Evolution of the Norwegian-Greenland Sea. Geol. Soc. Am. Bull. 88:969–999.2.0.CO;2>CrossRefGoogle Scholar
Testarmata, M. M. and Gose, W. A. 1979. Magnetostratigraphy of the Eocene-Oligocene Vieja Group, Trans-Pecos Texas. Pp. 55–66. In: Walton, A. W. and Henry, C. D., eds. Cenozoic Geology of the Trans-Pecos Volcanic Field of Texas. Texas Bur. Econ. Geology Guidebook. 19.Google Scholar
Vail, P. R., Mitchum, R. M. Jr., and Thompson, S. 1977. Seismic stratigraphy and global changes of sea level. Part 4. Global cycles of relative changes of sea level. Am. Assoc. Petrol. Geol. Mem. 26:83–97.Google Scholar
Van Andel, T. 1975. Mesozoic/Cenozoic calcite compensation depth and the global distribution of calcareous sediments. Earth Planet. Sci. Lett. 26:187–194.CrossRefGoogle Scholar
Van Couvering, J. A., Aubry, M.-P., Berggren, W. A., Bujak, J. P., Naeser, C. W., and Wieser, T. 1981. The Terminal Eocene Event and the Polish connection. Palaeogeogr., Palaeoclimatol., Palaeoecol. 36:321–362.CrossRefGoogle Scholar
Webb, S. D. 1969. Extinction-origination equilibria in late Cenozoic land mammals in North America. Evolution. 23:688–702.CrossRefGoogle ScholarPubMed
Webb, S. D. 1977. A history of the savannah vertebrates of the New World. Part 1. North America. Ann. Rev. Ecol. Syst. 8:355–380.CrossRefGoogle Scholar
Whitmire, D. P. and Jackson, A. A. IV. 1984. Are periodic mass extinctions driven by a distant solar companion? Nature. 308:713–715.CrossRefGoogle Scholar
Wilson, J. A. 1971. Early Tertiary vertebrate faunas, Vieja Group, Trans-Pecos Texas: Agriochoeridae and Merycoidodontidae. Texas Mem. Mus. Bull. 18:1–83.Google Scholar
Wilson, J. A. 1974. Early Tertiary vertebrate faunas, Vieja Group, and Buck Hill Group, Trans-Pecos Texas: Protoceratidae, Camelidae, Hypertragulidae. Texas Mem. Mus. Bull. 23:1–34.Google Scholar
Wilson, J. A. 1978. Stratigraphic occurrence and correlation of early Tertiary vertebrate faunas, Trans-Pecos Texas. Part 1. Vieja area. Texas Mem. Mus. Bull. 25:1–42.Google Scholar
Wilson, J. A. 1984. Vertebrate fossil faunas 49 to 36 million years ago, and additions to the species of Leptoreodon (Mammalia: Artiodactyla) found in Texas. J. Vert. Paleontol. 4:199–207.CrossRefGoogle Scholar
Wilson, J. A. and Schiebout, J. A. 1981. Early Tertiary vertebrate faunas, Trans-Pecos Texas: Amynodontidae. Texas Mem. Mus. Pearce-Sellards Ser. 33:1–62.Google Scholar
Wilson, R. W. 1972. Evolution and extinction in early Tertiary rodents. 24th Int. Geol. Congr. 7:217–222.Google Scholar
Wolfe, J. A. 1971. Tertiary climatic fluctuations and methods of analysis of Tertiary floras. Palaeogeogr., Palaeoclimat., Palaeoecol. 9:27–57.CrossRefGoogle Scholar
Wolfe, J. A. 1978. A paleobotanical interpretation of Tertiary climates in the Northern Hemisphere. Am. Sci. 66:694–703.Google Scholar
Wolfe, J. A. 1981. A chronologic framework for Cenozoic megafossil floras of northwestern North America and its relation to marine geochronology. Geol. Soc. Am. Spec. Pap. 184:39–48.Google Scholar
Wood, A. E. 1980. The Oligocene rodents of North America. Trans. Am. Phil. Soc. 70(5):1–68.CrossRefGoogle Scholar