Tuesday, April 24, 2012

Meristina brachiopod from the Keyser limestone

This is a brachiopod I found in an exposure of the Keyser formation called Meristina. It's fairly plain and featureless except for the sulcus.

Pedicle valve

Anterior

Brachial valve (weathered)

Posterior

Profile

The portion of the Keyser formation that I found this in is thin beds that are fairly shelly but have lots of complete specimens. This would indicate to me that it was a low energy reef like environment. Interestingly enough there are few bryozoans, coral or stromatoporids, which are typically the reef builders, in the same layer. So far I've not found any brachiopods in life position so it could represent a "pavement" or sorts that was periodically buried.

8 comments:

  1. I was wondering what County your Keyser FM find came from? I was also wondered if you could see a distinct Tonoloway FM limestone layer from the Late Silurian? If the formation is "Keyser" this brachiopod is most likely "Meristella nasutaformis" or "Meristella praenuntia" - I don't know one would ever tell the differnce. Regards - Jack

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    1. Jack, This came from Perry County at the "Delancy's Homestead" site mentioned in the "Fossil Collecting in PA" book. It's the only exposure of Keyser that I've found these brachs in.
      -Dave

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  2. Dave - I might have collected this site several times, but I'm not sure. I took Airport Rd off 284 by Andersonburg, PA North toward Rt. 17. I hunted the Keyser road cut about 2/3 of the way toward 17 on the East side of Airport Rd. I did not see the DeLancy Homestead or even a sign for it, but there was a dairy farm on the West side up from the road cut. The only large fossils I found were Leptaena and Atrypa sp. There were many different very small brachiopods. I also found many different bryozoans and Tentaculites - does this sound right?

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    1. Yep, that's the site! I spent some time pawing through the leaves at the base of the shallow pit walls and found a number of loose brachs, mostly Whitfieldella or Gypidula (I'm not quite sure). There are a number of layers that are chock full of these shells but rarely do they weather out alone. I've some that show brachidium preserved and I've even found some (mostly) intact crinoids there.

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  3. Dave - I must have missed the "pit". I've only hunted the road cut - maybe I should have climbed to the top. I did find Gypidula sp. - no Whitfieldella or crinoid's (except a few stems). I did find two different gastropods - Palaeozygopleura and Platyceras sp. Also found three different pelecypods - none whole and one was a Pecten sp. There also seemed to be a number of Leperditia ostracodes - I found several good ones. Regards - Jack

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  4. Hello
    I live in iowa and recently took up "artifact hunting". I came across a slab of limestone maybe 6 inches long and 4 across that is littered with brachiopods. I have no idea as to what specifically they are and was wondering if anyone here could help me? ajsimpkins@scciowa.edu

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    1. AJ,

      Your best bet is to go to: http://www.thefossilforum.com and post pictures of your find there. The members of that forum will be able to help you out for sure. -Dave

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  5. Hi Dave - A week ago I went on my yearly fly fishing & fossil hunting trip upstate to Potter Co. On the way I stopped at the Keyser FM site. Although this was the fourth time, I was more observant. I saw the marker for the DeLancey Homestead and explored the top of the formation. There was only a recently planted farmers field - although you could see some Lower Devonian plates under the dirt. I did not want to dig in the field so I want back to the road cut. I noted that someone had taken a front end loader and had taken out a lot of rock to make the "pit" you mentioned - it was not there last time I went. I did find several Meristina sp. and two straight ammonites. I also collected in the old mid-Dev. "Lesh Borrow Pit"; three Upper Dev. FM's in Tioga Co., and Silurian Mifflintown FM near Castanea. regards - Jack

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