Wyoming Baculite Identification Help

[Gregory Kruse]

Hello,

 

Last week, I found this baculite eroding out of a concretion in Casper, WY along the recreational bike path.  The shale erodes out of the hillside and is presumably part of the Cretaceous Cody Fm.  Can someone help me verify and identify this baculite?  Are there any references to the stratigraphy and or fossil assemblages in the Casper area? Sorry for the poor photo quality.  Thank you!

[val horn]

Quote

 

baculites suggest cretaceous marine, the other thing that this fossil suggests to me are belemnites,  which are also cretaceous, are mostly straight often translucent and lack the sutures that form baculites.

[minnbuckeye]

@jpc may be of help.

[PFOOLEY]

@jpc

CORRELATION OF THE UPPER CRETACEOUS STRATA OF WYOMING

 

Biostratigraphy of Santonian-Campanian genus Baculites in the Western Interior of North America

[Thomas.Dodson]

Definitely a Baculte and not a Belemnite. Some more pictures will help identification. A cross section picture of the broken part will be helpful. Is there any visible ribbing or sutures?

 

The Cody is divided into lots of members and certain Baculite species are specific to certain ages. If you can determine the member it will help. I see as I was typing this @PFOOLEYposted some references to that extent. His first source has a much nicer table than the one I was going to reference from Ammonites and the Other Cephalopods of the Pierre Seaway (1997). You can use that for maximum effect.

[jpc]

Hi Gregory-

I know exactly where you are in that photo.  Yes, baculite from the Cody Shale.  The Cody in and around Casper is Campanian in age, meaning not quite the end of the Cretaceous. I have collected a few from there but I find these things difficult to ID to species.  You generally need to have the sutures preserved, which yours doesn't so it may be best abeled as "Baculites sp.", meaning unknown species of the genus Baculites.  

[Gregory Kruse]

Thanks all for your suggestions and references!  Much appreciated!

- Greg

[jpc]

PS... even with the sutures preserved, they can be difficult to ID to species.  

[Gregory Kruse]

Yes, and I double checked that there were no sutures or ribbing present in this specimen.  Thank you again!

[caterpillar]

If you do not see any suture line, it may be that your specimen matches the body chamber of the shell

[FossilDAWG]

From the links that @PFOOLEY posted, it seems that the Casper area has exposures of two Baculites zones, Baculites sp (smooth) and Baculites sp (weak flank ribs).  Unfortunately these are about the least distinguishable species, and impossible without the suture.  BTW Baculites sp (smooth) is interesting in that it may be the same as Baculites inornatus from the Pacific coast, which may provide a point of correlation between the two areas. 

 

BTW I also struggle to confidently ID most of the Baculites species.  The people who can do it well have a lot of experience looking at a lot of specimens, as well as access to collections with very well preserved material.  Cobban revolutionized high resolution stratigraphy within the Western Interior sea by distinguishing the series of Baculites chronospecies that earlier workers mostly lumped together.

 

Don