Monday, October 31, 2011

Eospirifer eudora from Lockport, NY

Below is a brachiopod that I think is an Eospirifer eudora. It was found in the Irondequoit limestone Rochester Shale near Lockport, NY.  Mike at Louisville Fossils helped confirm the ID for me as it's also found in the Waldron Shale near him.

Pedicle valve


Brachial valve



The Irondequoit limestone Rochester Shale is a part of the Clinton group in New York. It's age is Silurian (Wenlockian epoch, Sheinwoodian stage).

Saturday, October 29, 2011

Rhynchotreta from Lockport, NY

While parsing through my findings from Lockport, NY I found this triangular shaped brachiopod. I believe it to be a Rhynchotreta as it bears some similarity to the specimen illustrated over at Louisville Fossils. While his were found within the Waldron shale of Kentucky (roughly equivalent to the Rochester Shale in NY) mine is from the slightly older Irondequoit limestone Rochester Shale. Both are dated to the Wenlockian epoch, Sheinwoodian stage of the Silurian.

Pedicle valve


Brachial valve



I'm finding scattered references to a species called Rhynchotreta americana around the internet while searching for info about the Irondequoit limestone. Apparently this is a common species name used for this shell within Silurian rocks.

Thursday, October 27, 2011

Leptaena from Lockport, NY

Leptaena is a common Strophomenid type brachiopod that ranges from the Ordovician thru the Carboniferous periods of the Paleozoic. I've written about it before in this post. The specimens below come from the Irondequoit limestone Rochester Shale which is part of the Clinton Group and is lower Silurian (Wenlockian epoch, Sheinwoodian stage) in age. I found them in a railroad cut west of Lockport, NY. The first specimen has a hitchhiker in the form of a Bryozoan.

Pedicle valve


Brachial valve


This is a larger specimen found at the same cut but only the pedicle valve is exposed.

Tuesday, October 25, 2011

Leperditia Ostracods from the Tolonoway Fm.

While exploring an outcrop of Silurian aged rock near Mexico, PA I came across some large Ostracod fossils. I was searching for an outcrop of the Keyser formation (Pridoli-Lochkovian) which overlies the Tolonoway formation (Ludfordian-Pridoli). Here is a small plate of limestone with a few of the valves preserved. 

The size of the fossils was surprising to me as most species of Ostracod are much smaller, on the order of mm, not cm. The specimen below is about 1.5cm in length.

Another valve

I was tentative on the ID of the genera as Leperditia as they are known from the Tolonoway formation that I was searching in. I didn't confirm the ID until recently after I received a specimen from a new trading partner in France, Christian. He sent me the below specimen of a Leperditia from the Silurian (Wenlockian) aged rocks of the island of Gotland, Sweden.

The size and shape of the shell are the key indicators you have a Leperditia. Note the straight hingeline along the top edge of the shell also. Ostracods are arthropods from the Crustacea class and thus are related to Crabs, Shrimp and even Barnacles.They live within a bivalved shell swimming freely in the water or crawling along the bottom of the sea.

Sunday, October 23, 2011

New (for me) Trilobites from Arkona

I don't find whole Trilobites often from the Devonian and when I do they are usually the genera Phacops. That is why I was so pleased to add two new Trilobite species to my collection. Both come from the Middle Devonian (Givetian) aged Widder Formation (Hungry Hollow member) near Arkona, Canada.

First up is a partial Basidechenella that is enrolled next to an enrolled Phacops Trilobite (2 for 1!). As you can see in the picture below the much of the cephalon is missing but the presence of a margin along the edge gives it away.

This is a view of the thorax with the partially exposed Phacops cephalon below.

Now a view of the enrolled Phacops with the Basidechenella at the bottom. This is the first intact (enrolled or prone) specimen of Phacops that I've found at Arkona.

The other new genera is this pygidium from a Crassiproteus. It's small but unique enough to be identifiable.

Adding the specimens above to my collection, along with an intact Greenops from higher in the Widder Fm., gives me four genera of Trilobites from the Widder Fm. If I ever get the chance to collect down in the Arkona Fm. (the next formation below the Hungry Hollow mbr.) then there are several more genera that I could find.

Friday, October 21, 2011

Mediospirifer "Angustus" ?

During a recent trip up to Arkona, Canada I found this unusual Brachiopod which resembles the mutant off spring of a Mucrospirifer and a Brachyspirifer. It comes from the Middle Devonian (Givetian) aged rocks near Arkona called the Hungry Hollow member of the Widder Formation.

Stumped as the to ID of this odd looking Spiriferid, I looked it up in the most comprehensive resource available to me: Amadeus Grabau's "Geology and Paleontology of Eighteen Mile Creek" and it seems to match Spirifer("Mediospirifer") angustus (Page 213). The problem is this is not listed as a species that is found within the Widder formation. This is based on the 1958 publication "Checklist of Fossil Invertebrates Described from the Middle Devonian Rocks of the Thedford-Arkona Region of Southwestern Ontario by the University of Michigan.

So I may have found a new species that was not known from the Widder formation before now. Has anyone else seen a Brachiopod like this before?

Wednesday, October 19, 2011

Reassembled coral from Arkona

When collecting in the field often one finds many loose fragments of larger, and more delicate, fossils. Among the most commonly found are Crinoids (stems, calyx pieces), Bryozoans (thin branches or lace like fronds) and branching or "finger" corals. On a trip to Arkona, Canada I managed to collect a number of fragments of a branching type coral and have subsequently reassembled them.

It's a rough composition but not too bad. Some pieces were still part of a larger rock and I broke them out so the finished piece would be more complete. It looks like this may be a species of Favosites coral but I'm not sure which. The specimen comes from the Hungry Hollow member of the Widder formation which is Middle Devonian in age.

There are some interesting things that can be noticed by studying the reassembled specimen. It is fairly flattened, possibly by compression, but it once did stand upright in on the sea floor. This is evidenced by the fact that there are corallites on all sides of the branches. There doesn't seem to be any regular pattern to the growth of the branches as they twist and turn randomly and in some cases come fairly close to touching. I don't see evidence of epibonts or predation so I'd say the burial was during a storm that probably smothered the polyps.

One day I hope to clean all the remaining rock off of the pieces so that it will look more like the way it once did. I was inspired to do this by my love of puzzles and by my friend Joe who has done similar projects for a Cladopora coral from Arkona.

Monday, October 17, 2011

Sowerbyella from Schullsberg, WI

Back when I was mostly interested in collecting minerals I purchased this piece as it came from a zinc mine near Schullsburg, Wisconsin. It is a piece of shale with two Sowerbyella brachiopods on it and they have an odd yellow color to them.

This one is a complete shell with both valves (or maybe it's just one that was flipped over?).

The other is a partial of the brachial valve and you can see the muscle attachment scars.

Sowerbyella is an Ordovician genera but if anyone has any more information on where they may originate, formation wise, please let me know.

Saturday, October 15, 2011

Cystiphyllum from the Jeffersonville ls.

Cystiphyllum is a common fossil Rugose coral from the middle Devonian so it's no surprise to find them in the Jeffersonville Limestone near Louisville, KY. These are two specimens that caught my eye for their unusual look.

This first piece has had portions of it's Calcite skeleton replaced with white quartz.

The layering is very obvious in the specimen and they are due to regular growth of the coral.

Cystiphyllum gets it's name from the botryoidal, cyst like growth pattern that is found within the calice.

This next specimen is interesting because the quartz replacement is very irregular so it looks like a patchwork quilt.

This allows for "windows" where one can see the exterior wall and it's ornamentation while also seeing into the coral skeleton. I like how you can see the "cyst" shapes as concave shapes rather than the usual convex.