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Microvertebrate concentrations: Figures

Figure 1. Shrew upper molar from TVOR Site, Miocene of Fort Polk, Louisiana. Occlusal view. Scanning electron micrograph by Xiaogang Xie and Suyin Ting.
Figure 2. Location map showing Fort Polk in Louisiana, and Big Bend National Park and Coldspring in Texas. Permits are required for research on Fort Polk and in Big Bend National Park.
Figure 3. Lateral view of merychippine horse mandible encased in pedogenic nodular material from DISC Site, Miocene of Fort Polk, Louisiana. Photograph by Kerry Lyle.
Figure 4. Joe's Bonebed, Paleocene Black Peaks Formation, Big Bend National Park, Texas. Fluvial mudstone slopes are heavily covered with pedogenic nodules. Remains of large and medium-sized vertebrates were recovered from float all along the slope pictured here. A small lens of nodule conglomerate from this slope yielded the microvertebrate fauna from Joe's. Suyin Ting (L), Joe Schiebout (M), and Jill Hartnell (R).
Figure 5. Judy's conglomerate, Late Cretaceous, Aguja Formation, Big Bend National Park, Texas, with Julia Sankey. Photograph by Jean Sankey.
Figure 6. LSU field crew wet screening untreated mudstone in the Rio Grande, Big Bend National Park, Texas.
Figure 7. Robert Rainey (L) and Judith Schiebout (R) bag conglomerate at Joe's Bonebed, Big Bend National Park, in 1970. Photograph by John A. Wilson.
Figure 8. Helicopter carries bags for screening from remote sites in Big Bend National Park, Texas in 1984.
Figure 9. Bags of rock from the Louisiana Miocene as brought in from the field, closed with duct tape. Airless jackhammer and conglomerate piece from Stonehenge Site rest on the bags.
Figure 10. Slabs of conglomerate from Stonehenge Site, Miocene of Fort Polk, which have been removed by heavy equipment from a gully where they were exposed. Later, they were broken up by gasoline-powered jackhammer for bagging. Robert Hays (L) and Suyin Ting (R). Photograph by Pam Borne.
Figure 11. Dumping a screen on a drying tray.
Figure 12. Dried screening residue from Stonehenge Site showing nodules darkened with iron and manganese oxides. Dr. Schiebout indicates a bone fragment.
Figure 13. Dried screening residue from DISC Site showing nodules larger and lighter colored than those from Stonehenge Site.
Figure 14. Dr. Ting in goggles and respirator, facial protective gear worn during handling of the glacial acetic acid.
Figure 15. Dr. Ting and Casey Foote in protective gear are preparing to pump acid from the 55-gallon barrel for dilution to 10% and addition to the plastic boxes of rock. Rock saw in background is not used in this project.
Figure 16. First lower molars of the rodent Copemys, illustrating mounting and numbering method used for microvertebrate fossils from the Miocene of Fort Polk. Gray clay holds the row of capsules in place.
Figure 17. Judy's conglomerate, cross sectional view, Late Cretaceous, Aguja Formation, Big Bend National Park, Texas. Nodules and bone pieces show as white flecks. Photo by Julia Sankey.
Figure 18. Dry (L) and wet (R) pieces of Julia's conglomerate from the Late Cretaceous, Aguja Formation, Big Bend National Park. Photo by Julia Sankey.
Figure 19. Weathered, man-made surface of the main conglomerate at DISC Site, Miocene of Fort Polk. It will be broken up with sledge or airless jackhammer and shoveled into bags.
Figure 20. Incisor on weathered surface of the main DISC conglomerate.
Figure 21. Cleaned cross sectional surface showing contact of main conglomerate from DISC site and underlying overbank mudstone.
Figure 22. Erosion at DISC Site revealing several minor layers of pedogenic nodule conglomerate.
Figure 23. TVOR Site conglomerate, Miocene of Fort Polk, being photographed by geoarchaeologist Timothy Dalbey of the Corps of Engineers, Fort Worth District This is a color version of Figure 2 of Jones et al. (1996) and Photograph 8 of Schiebout (1997b). Site looks very similar to its appearance when first discovered.
Figure 24. Close up, cross sectional view, of the conglomerate at TVOR Site showing both fresh dark surfaces which have been broken and lighter colored weathered surface. Cross bedding is evident.
Figure 25. Thin section from lower part of DISC main conglomerate under polarized light. "A" indicates a nodule showing septarian cracks and "B" is a partially dissolved nodule. Scale = 1 mm. This is a color version of Photograph 13 (Schiebout 1997b). Photograph by Julitta Kirkova.
Figure 26. Thin section under polarized light, cut a few cm higher than Figure 25, from the upper part of the main conglomerate at DISC Site, showing more quartz sand. Scale = 1 mm. Photograph by Julitta Kirkova.
Figure 27. TVOR Site conglomerate under polarized light, showing rounded nodules and sand in a calcite cement. "A" indicates a nodule and "B" is a quartz grain. Scale = 1 mm. This is a color version of Photograph 12 (Schiebout 1997b). Photograph by Julitta Kirkova.
Figure 28. Sawed, cross sectional surface of a conglomerate boulder from a site near Coldspring, Texas at which mammals of the Miocene Cold Spring Local Fauna had been recovered.
Figure 29. Erosional gully, TVOR S Site in the Miocene of Fort Polk, shows a pedogenic nodule conglomerate, indicated by an arrow. This site is a kilometer from TVOR. Photo by Megan Jones.
Figure 30. Close up of conglomerate seen in Figure 29. Photo by Megan Jones.
Figure 31. Nodule encrusted and cracked large mammal bone in place at Joe's Bonebed in mudstone of the Paleocene Black Peaks Formation in Big Bend National Park, Texas.
Figure 32. Mandible of Prosynthetoceras francisi exposed by weathering of a man-made surface at DISC Site. Displacement of the piece of the mandible from the rest may have resulted from the passage of heavy machinery over the site. An arrow indicates the displaced piece.
Figure 33. All fossils from a preliminary picking of the main conglomerate at DISC Site, Miocene of Fort Polk. Teeth and identifiable bone will be removed in a second picking. This is a color version of Photograph 16 (Schiebout 1997b).
Figure 34. All mammal teeth from a session of picking at TVOR Site. A geomyoid rodent tooth is indicated by the arrow.
Figure 35. 300-counts of kinds of fossils from TVOR Site (A, B, C) and DISC (D). Figure 35C is modified from figure 8 and 35D is modified from figure 7 of Schiebout (1997b).
 
   
   
   
Figure 36. Bivariate plot of length versus width of the first lower molars of the rodent Copemys from sites on Fort Polk, Louisiana and from Coldspring, Texas. Three sites on Fort Polk, Stonehenge, Gully, and DISC, crop out in ascending stratigraphic order, and TVOR is probably stratigraphically lower than Stonehenge, although lack of outcrops makes this uncertain.