Data: These were found in Southern Wyoming. Elevation is about 6500 ft.

Email: William

Discussion:

• Southern Wyoming has nice exposures of the Green River Formation (Eocene), deposited in vast lakes. The snails are probably Juga, though in popular literature they are often misidentifed as "Turritella". Most of the other specimens are bivalves (not brachiopods-they have left and right valves, not top and bottom valves, and the fact that many are molds with the shell lost suggests aragonitic bivalves rather than calcitic/phosphatic brachiopods).
  Possible non-marine bivalves would include unionoids and corbiculids, but I don't know the full fauna of the region.
  There are also lots of vertebrates (if you have a whole fossil fish, it's probably from the Green River Formation).
  Dr. David C.

• Greetings,

  I was searching the web for mollusk resources, when I stumbled across your website and the 'mystery' section. I took particular interest in these shells from Wyoming: (I am unable to do much formatting with gmail and so if anything is unclear, please feel free to ask me)

  The "possible Juga" is Goniobasis tenera (now Goniobasis is considered synonymous with Elimia, however, I've had an interesting yet brief discussion with R.T. Dillon at COFC about this (http://www.cofc.edu/~dillonr/cvweb.htm)

  The bivalves are Pleiselliptio priscus (more ovate shape) and P. littoralacustris (more circular).

  The ID is based on J.H. Hanley's PhD dissertation (Hanley is now deceased), which is the most thorough analysis of the mollusks of the Green River Formation. I don't have the original references handy, however, so I can't remember who coined the name. I did my master's work on the Green River, so I have spent quite some time with these
  fossils.

  There are numerous collectors who label gastropod fossils from the Green River as 'turritellids' - these are all the internal casts of Goniobasis tenera. These shells are often found in thick coquinas and these rocks are cut and polished and labeled "Rattlesnake Agate" in some rock shops. There are a few other species of snail from the green
  river, but rarely are they collected in any quantitiy (Viviparus sp. is the other that comes to mind).

  I've included a short bibliography of some more recent GR mollusk papers. I'm working on pleistocene terrestrial gastropods for my PhD, but have a soft spot in my heart for the Green River.

  Hanley, J.H. 1974. Systematics, paleoecology, and biostratonomy of nonmarine Mollusca from the Green River and Wasatch formations (Eocene), southwestern Wyoming and northwestern Colorado. Unpublished Ph.D. dissertation, University of Wyoming, Laramie, Wyoming, 285p.

  Hanley, J.H. 1976. Paleosynecology of nonmarine Mollusca from the Green River and Wasatch Formations (Eocene), southwestern Wyoming and northwestern Colorado, in scott, R.W. and West R.R., eds. Structure and Classification of Pleocommunities: Stroudsburg, Dowden, Hutchinson and Ross, p. 235-261.

  Hanley, J.H. and Flores, R.M. 1987. Taphonomy and Paleoecology of Nonmarine Mollusca: Indicators of Alluvial Plain Lacustrine Sedimentation, Upper part of the Tongue River Member, Fort Union Formation (Paleocene), Northern Powder River Basin, Wyoming and Montana: Palaios v.2. p. 479-496.

  Kuchta, M.A., Geary D.H., Carroll, A.H., 2000, Utility of nonmarine mollusca as paleoenvironmental indicators in the Green River Formation, Wyoming, Abstracts with Programs - Geological Society of
  America, v. 32 no. 7, p. A12.

  Kuchta, M.A., 2000, Paleoenvironmental significance of nonmarine mollusca in the Luman Tongue of the Green River Formation, Wyoming, Unpublished Master's Thesis,
  University of Wisconsin, Madison, 65p.

  
  Cheers,
  -matt kuchta

  --
  Matt Kuchta
  PhD student at UW Madison
  (hiding out on the north shore)
  210A Heller Hall, UMD campus

  
  

• possibly a turritella species...Avril B.
• probably Juga...Dr. David C.

11. 20x5 mm

Discussion:

• possibly a turritella species...Avril B.
• probably Juga...Dr. David C.

12. 30x7 mm

Discussion:

• possibly a turritella species...Avril B.
• probably Juga...Dr. David C.

	10x7 mm
	16x8 mm

 

13. 30x10 mm

Discussion:

• possibly a turritella species...Avril B.
• probably Juga...Dr. David C.

• possibly a turritella species...Avril B.
• probably Juga...Dr. David C.
  

a tooth (claw) from North-central Wyoming

It measures 10 mm long (broken) 5mm wide at large end and 3mm at tip. The tip has been worn down.

Discussion:

17. 47x32x17 mm

Discussion:

• possibly a brachiopod species...Avril B.
• bivalve...Dr. David C.

• probably Juga...Dr. David C.

• probably Juga...Dr. David C.

20. Inset of above (Left of #18.): There appears to be snails within the fossilized snail!!
Larger snail is 6x4 mm

Discussion:

• Have smaller turritella shells washed into and fossilized in larger turretla shells? ...
  Avril B.
• probably Juga...Dr. David C.