Brigham Young University BYU ScholarsArchive Theses and Dissertations 1977-08-01 The Sage Creek Mountain local fauna of the Bridger Formation near Lonetree, Wyoming Steven W. Barker Brigham Young University - Provo Follow this and additional works at: https://scholarsarchive.byu.edu/etd Part of the Life Sciences Commons BYU ScholarsArchive Citation Barker, Steven W., "The Sage Creek Mountain local fauna of the Bridger Formation near Lonetree, Wyoming" (1977). Theses and Dissertations. 7620. https://scholarsarchive.byu.edu/etd/7620 This Thesis is brought to you for free and open access by BYU ScholarsArchive. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. I.dz. I f}1f-l Jf11 A 'lhesis De_pe:r.tment of Zoology Br1gham Young Universjty In Partial Fulfillment of the Requirements for the Degree Master of Science August 1977 'I.Li_ s tLesls by Steven W Barker is accepted in its present :fonr, bJ -Lbe Dep::i..Ttrr.ent of Zoolol::;y- o:r' Brigham Young University as satisf;yi1.tg the thed.s requi:remnit :fer the degree of Master of ScienC€. i:l A CKNOWLF:!DGBMRNTS Grateful acknowledsement lr; made for the guidance and assistance given by the chairma.n of my a.clvisory com.mittee, Dr. Wade E. Miller, and. the otba:r: ccmmi ttee members, Dr. J. Keith Rigby Sr, and Dr. Clive D. Jorgensen. Acknowledgement i.s also given to Dr. J, Keith Rigby Jr, a.nd Dr, Robert M. West for their valuable suggestions and guidance. I thank uy wi:fe, Holly, fo::c her inspiration, patience and the help she gave me in the fleJ.d and. -.d.th preparation of thh: thesis, iii 'I'.A:BIJiiO 1'' CONTF!NTS Page ACKNOWLEDGFJ.IENTS iii LIST OF '.f:ABLES vi LIST OF :B'IGURES• vii INTRODUCTION 1 HIS'IORY O:B'INVES'rIGATION 2 METHODOLOGY. 4 Abbreviations Used in This Study. 6 GEOLOGY. 8 FOSSIL DISTRIBUTION • SYSTEMATICS. 16 Class Osteichthyes. 16 Class Reptilia . 17 Order Chelonia 17 Ord.er Crocodilia 18 Class Mammalia. 19 Order Creodonta. 19 Order Carnivor-~. 21 Ordei:· Primates 22 Order Rodentia 24 Ord.er Pantodonta 25 Order Condylarthra 26 Order Perissodactyla 28 AGE AND CORRELATIONS 35 CLIMATEAND ENVIRON111ENT• 37 iv Page CONCLUSIONS 38 LITERATURECI1ED. 39 APPENDIX 43 V LIST OF TABLES Table Page 1. Cornposi tion of zones C and D of the Sage C..'reek i1ountain local Fauna • • • • • • . ~ . 1.5 vi LIS'l' OF F'IGURES Figure Page 1. Index Map. The area of study is 9,7 kilometers north of Lonetree Wyoming, at the base of Sage Creek Mountain • • • • • • • • • • • • • • • • • • • • • • • 5 2. Area of study ( taken from the United States Geological Survey 7.5 1 maps of Lonetree and Reed Reservoir, Wyoming Quadrangles (1961+) Section 9, Township 13 North, Range 113 West) • . • • • • • • • • • • • • 7 J. The study area (viewed from the west) showing position o:f Bridger zones C and. D, and_ the Lone tree White I,a,yer . • • • . • • • .. • • '> • • • • • • • • • • • • 12 vii IN'J'RODUC'l'ION The Bridger Formation in the Green River Basin has been divided into two members, the lower Black's Fork member and the upper T!,-d.n Buttes member. 'Ihe Black's Fork member is composed of' biostratigraphlc zones A and Band the Twin Buttes member is com- posed of biostratigraphic zones C, D and E. Recent workers have found that zones A and B contain the same fauna and therefore represent just one biostratigraphic zone (McGrew 1971, Robinson 1970). Future studies of the biostratigraphic zones of the 'fwin Buttes member are necessary to determine if the C, D and E zones are valid. Some are currently being conducted, In the present study fossils were collected from Section 9, Township lJ North, Range 113 W2st in the Green River Basin of southwest~,rn Wyoming. These fossils were critically examined and identified. in order to determine the biostratigraphic validity of zones C and D. Zone E was not present here. Fossil fragmentation and paucity restrict the deg:ree of chrouologic precision. 1 HISTORY OF' INVESTIGATION One of the earliest descriptions of Green River Basin features was written by Ball (18J5:3), who described it as c=i,n immense prairie with little vegetation upon which herds of buffalo fed, later, Fremont, enroute to Fort Bridger, collected and discussed a number of gastropods from near the fort which were later described by Hall in J:!"'remont's 1845 report, A number of pre-Civil War geological surveys were conducted along various immigrant trails and wagon roads. During this period, beginning in 18 58 with a field survey :r-eported by lander, pale onto- logical investlgations began in the southern Green River Basin (lander 1859), The first Green River Fossil fish were collected by Evans, and. later described by Leidy in 1856. 'l'he Bridger Formation was named by Hayden in 1869. At that time he wa.s conductiri.g territorial surveys concurrently w-ith Powell and Klng. Most of the work was done along the UJ,.ion Pacific H.ail:road's right-of-way, During one of these surveys Carter col- lected a fossil primate in the Grizzly Buttes near Fort Bridger, which was identified as Omomysby Leidy in 1869 (Hayden 1873). Cope also collected vertebrates in conjunction with the Hayden survey of 1872 and 1873. Early intensive explorations of the Bridger Formation were carried on for a number of years by Marsh of Yale 2 University, which resulted in a s0:rles of short papers between 1871 and 1875. 0ne of his most im:po.rtant papers was "Preliminary Description;:; of New Tertiary Ma!itmals"(1872), later, Wortman (1901, 1903), Troxell (1930), and Wilson (19.38) conducted studies based on Marsh's explorations. Detailed stratigraphic studies of the Bridger area began shortly af'te:r· the turn of the century (Veatch 1907, Schultz 1914). In the early 192C's Bradley began a long study of the Green River fu.sin, which culrr..inated in his 1964 U.S. Geological Survey Professional Paper, the first complete study of the basin and adjacent areas. Osborn (1902, 1929), Matthew (1909, 1910), Granger and Gregory (1917), Wood (1934) and Gazin (1959) all did extensive geological and vertebrate paleontologica~ research in the basin. Their colleet:i.ons are now at Princeton University and the American Museum of Natural History. Recently, many additional workers have been doing more detailed work and adding to the knowledge of the abundant :Bridger fauna, e.g., McKenna (1960), Simpson (1933), Robinson (1957, 1966, 1967), and West (1969, 1970, 1972, 1973). MET'riODOLOGY 'Ihe study area is on the southwest, slopes of Sage Creek Mounta:tn 9. 7 km north of Lonet-cee in the Green Hiver Basin of southwestern Wyoming (Fig. 1). 'Ihe topography consists of gently rolling hills with locally developed badlands at an average elevation in excess of 2,550 meters. Exposures are entirely of the Bridger Formation. Verte bra.te fossils, mostly mammalian, are relatively commonthroughout the area, although some stratigraphic zones yield more abundantly than others. 'l'he United Sta·tes Geological Survey 7. 5' topograph1c:J.l maps of the Ionetree, Wyoming Quadrangle and the Reed Reservoir, Wyoming Quadrangle of the 1964 series were used to determine location and areal extent of the study area, which consisted of Section 9, Township 13 North, Range 113 West, Uinta County, Wyoming. All vertebrate remains observed, with the exception of highly fragmented turtle sh0lls, were collected and their locations marked on an enlarged t-0pographic map (Fig. 2). Notes indicating stratigraphic position of each specimen, associations with other vertebrate fossils, sto ..te of preservation and condition were taken. Highly fragmented turtle remains are common. Fragmenta,tion is due to ice wedging and wandering livestock, 'Ihe lx-::st preserved turtle specimens 4 _____.,--- -- Fort Bridger {t~r--.---i -·---' Lyman 5 Kilometer~ _,,__M_i-11:-·v_r_n_er_- L M~~;~-1 View ~ ...... ✓ ' I () (I) I I 3'.:..,o I I :r (t) (C I I • (1) (I) I ' ,.- I \ I \ I \ \ I. \ I Stuci'y,..,,, ~ Area NORTHi WYOMING Lonetree II '·, ..---~-~---' ' Fig. 1. Index Map. T'ne area of study is 9,7 kilometers north of 1.one-t.ree Wyoming, at the oo.se of Sage Creek Mountain, were collectea, More productive locations were dry screened for smaller ve:cte brafos through 6 mm and 2.'ll.msieves, respect.i vely. Fossi1B were identified as acc1u·ately as possible with reference matP.~d.als availabJe to the author. Measurements of small bones and. teeth were made with dlal ~alipers to the nearest tenth of a millimeter. The classificatlon used by West (1973) was adopted for use in this study. 'lhe rock uni ts present in the study area were examinect and identified in outcrop and hand samples. No petrographic or sieve analyses were conducted. Only gross sedimentary structures and textures were noted. For the most part Bradley's 1964 U.3. Geological Survey Professional Paper of the geology of the Green River Bashi was followed for identification of the Bridger C and D Meml::.ersa:nd locating the member boundaries. Abbreviations Used in 'Ibis Study AM-Amherst College, Massachusetts BYU-Brigham Young University, Utah USNM-U.S. National Museum., Washington, D.C. ANMH-American Museum of Natural History, New York YPM-Yale Peabody Museum, Connecticut ~ Scale l: 24,000 1,000 Feet i305 M5'tersl Contour Interval 50 Fe•H ( 12.2 Meters) Fie;. 2 Area of' study (taken from the United States Geological Survey 7,5' maps of the Lonetree and Reed Reservoir, Wyoning Quadrangles (1964), Section 9, Township 13 North, Range 113 West).