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Thursday, June 21, 2012

Tornoceras arkonense from Arkona

I'm a little surprised that I hadn't posted a specimen of Tornoceras arkonense to my blog yet. It's a small cephalopod that is found only in the Arkona formation at the site where I collect at Hungry Hollow along the Ausable river in Ontario, Canada. The fossils are preserved by pyrite and can be very detailed. below is a typical specimen with views of the suture in profile and from the front.



The Arkona formation is middle Devonian (Givetian stage) in age.
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5 comments:

  1. AnonymousJune 21, 2012 at 5:19 AM

    Hi Dave - I have five of these (all with pyrite) from Arkona, but they are all labeled as "Tornoceras uniangulare" by the various folks that sold them. How does one tell the difference?

    regards - Jack

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    1. DaveJune 22, 2012 at 4:28 AM

      Jack, T. arkonense is only found within the Arkona formation which is where I found these. I think when the conch gets larger and is found within the Widder formation then it's T. uniangulare. At least that is what I've been told by local collectors. -Dave

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  2. AnonymousJune 22, 2012 at 5:20 AM

    Dave - I have five from the Arkona FM and four from the Widder FM - all named Tornoceras uniangulare by those individuals I purchased them from. If they are different, I can't tell so I probably need to do some literature work. I also have found several Tornoceras uniangulare in the Mahantango FM over the years - these are larger than both the Tornoceras coming out of the Arkona FM and Widder FM. - regards Jack

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    1. DaveJune 23, 2012 at 12:57 PM

      Jack, From what I know, and talking to a few others, if it was found in the Arkona fm then they are only T. arkonese. If they were found in the Widder then they are three possibilities: T. widderi, T. mesopleuron and T. uniangularie. I've found what I think are T. uniangularie and Agoniatites sp. in the Mahantango: http://viewsofthemahantango.blogspot.com/2010/05/goniatites.html

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  3. AnonymousAugust 7, 2012 at 3:50 PM

    i remember going on a high school field trip to the HH years ago. i split from the group and wandered the banks alone for hours and i never found anything half as good as that.

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