Ruger9a Posted January 3, 2021 Share Posted January 3, 2021 Good evening folks. I have two items from the Fox Hills Formation that I recently prepped that are in need of identification. All help is appreciated. 2 Link to comment Share on other sites More sharing options...
Ruger9a Posted January 3, 2021 Author Share Posted January 3, 2021 And the last photo. Link to comment Share on other sites More sharing options...
Thomas.Dodson Posted January 3, 2021 Share Posted January 3, 2021 What area of the Fox Hills formation and do you know what member? The first looks like a Graphidula sp., probably Graphidula culbertsoni. The ammonite I'll wait for more information to narrow it down but it probably won't be too difficult. 1 Link to comment Share on other sites More sharing options...
Ruger9a Posted January 3, 2021 Author Share Posted January 3, 2021 I believe it's Timber Lake. Link to comment Share on other sites More sharing options...
Ruger9a Posted January 4, 2021 Author Share Posted January 4, 2021 2 hours ago, Thomas.Dodson said: What area of the Fox Hills formation and do you know what member? The first looks like a Graphidula sp., probably Graphidula culbertsoni. The ammonite I'll wait for more information to narrow it down but it probably won't be too difficult. @Thomas.DodsonTom, I can't seem to find anything on the Graphidula culbertsoni in wiki or google. Any suggestions? Link to comment Share on other sites More sharing options...
Fossildude19 Posted January 4, 2021 Share Posted January 4, 2021 LINK 2 Tim - VETERAN SHALE SPLITTER VFOTM --- APRIL - 2015 IPFOTM -- MAY - 2024 _________________________________________________________________________________ "In every walk with nature one receives far more than he seeks." John Muir ~ ~ ~ ~ ><))))( *> About Me Link to comment Share on other sites More sharing options...
Thomas.Dodson Posted January 4, 2021 Share Posted January 4, 2021 23 minutes ago, Ruger9a said: @Thomas.DodsonTom, I can't seem to find anything on the Graphidula culbertsoni in wiki or google. Any suggestions? https://www.google.com/books/edition/U_S_Geological_Survey_Professional_Paper/9LZVJMbjxXYC?hl=en&gbpv=1&dq=Graphidula+culbertsoni&pg=SL2-PA31&printsec=frontcover J. Mark Erickson's "Revision of the Gastropoda of the Fox Hills Formation, Upper Cretaceous (Maestrichian) of North Dakota 1974" has a lot of information on the complexity of the genus and the closely related genus Piestochilus, perhaps more information than you'd want to know. Basically Erickson revised these gastropods on pleural angle and whorl convexity because of the presence of varying number of columnellar plaits within a species and from immature and adult specimens. In my experience G. culbertsoni is the most common of these gastropods in North Dakota and the few Fox Hills places I used to collect in South Dakota. I can't seem to find a digital copy. I bought a paper copy a while back. Meek and Hayden's original report also has good plates. There's one picture on Cretaceous Atlas. https://www.cretaceousatlas.org/species/graphidula-culbertsoni/ Here are a couple I posted in my Fox Hills gallery. Regarding the ammonite I'm leaning towards a Discoscaphites sp. A closer picture of the umbilicus, the flank, and the aperture might help. Discoscaphites conradi is rarely found in the Timber Lake Member so I'd expect an immature Discoscaphites gulosus. How many rows of flank tubercles are present? Discoscaphites rossi is only found from the Timber Lake Member on the Cheyenne-Moreau divide and bluffs on the north side of the Moreau River, Dewey County, South Dakota. I've never personally seen one of these. 3 Link to comment Share on other sites More sharing options...
Ruger9a Posted January 4, 2021 Author Share Posted January 4, 2021 @Thomas.Dodson THANKS so much for all your help. The number of tubercles looks like four to me, two on the top and two rows on each side. I looked up the reference you provided and it appears to be a match. Link to comment Share on other sites More sharing options...
Thomas.Dodson Posted January 4, 2021 Share Posted January 4, 2021 Two rows of flank tubercles fits in Discoscaphites gulosus. I wasn't sure because I only saw one in the photo but that's good. 1 Link to comment Share on other sites More sharing options...
Ruger9a Posted January 5, 2021 Author Share Posted January 5, 2021 Thanks again Thomas!!! Link to comment Share on other sites More sharing options...
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