Brachiopod from Madison group Misson

[David Powers]

I have a brachiopod taken from the Madison group, Mission Canyon member. I am working on species. I’m thinking it is rafinisquina ponderosa  or strophomena vetusta. I’m not sure. I can use some help.

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[Asa Kaplan]

David, nice fossil. If this is definitely from the Madison Limestone then it is Mississippian in age — far too young to host Rafinesquina or Strophomena. I do concur that it is a strophomenide brachiopod, most likely an orthotetidine.  This article is a good jumping-off point:

https://imnh.iri.isu.edu/digitalatlas/geo/gsa/papers/gsac1p4.pdf

[David Powers]

Hi Asa Kaplan,

Thanks for the link to the PDF. I saw that article before. I didn’t save the article for future use.  I wasn’t sure the age of the limestone. I found this article “Type Sections of the
Madison Group (Mississippian)
and its Subdivisions in Montana
GEOLOGICAL SURVEY PROFESSIONAL PAPER 842”
This article identifies the area to the mile where I found the brachiopod.  I will now use the linked article you’ve given to narrow the species. I will be looking at the  ones you named to see how they line up with what I have.

Cheers

David

[Asa Kaplan]

For a more extensive list of candidate brachiopods, see

http://ftp.maps.canada.ca/pub/nrcan_rncan/publications/ess_sst/122/122462/bu_378.pdf

Among orthotetidines, this publication lists only Schellwienella? cf . S. alternata Weller, 1914, with some good photos on plate 1.

 

[David Powers]

Hi Asa I’m looking at the publication.

Thank you

David

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