Bridgeport, Tx Fossil Trip

[silverphoenix]

I went to Bridgeport a few weeks back to collect microfossil matrix. I collected a few buckets of material before the sun set as I got there around 6PM on the way back from Jacksboro. I processed the matrix and took some with me to sort on the rig while waiting to take surveys (MWD).

This is the Jasper Creek Formation of Texas, Pennsylvanian in age. This is just from two 8oz bags of processed larger 1/4" to 1/2" matrix. About 1/3 of this matrix is fossils, at least identifiable. Tons of crinoids, some sort of spherical fossils (ID anyone?), horn corals, crinoid plates, etc. I have a few buckets processed--I'll be donating the vast majority of the larger material to the HGMS show this year for kids to sort through. The exposure was very small but completely saturated in fossils. I can't wait to see what all the kids find--maybe some trilobites, who knows!

Edited November 1, 2014 by silverphoenix

[tmaier]

Wow, that is rich material.

I don't know what those round nodules are, they seem to be a part of crinoid, but notice that some of them show a stem going in one side and a stem of equal size coming out the other side. Since there is such a high proportion of them, I would guess they are part of those crinoid stems you show.

The rugose coral pieces might be lumped in to the genus Zaphrentis, unless somebody has a better place they belong. If you look at the wide end, the Zaphrentis should have a groove that splits it bilaterally, and sometimes a deep notch on one side. The flatness of that rugose is one clue that it might be Zaphrentis, because the flatness is sort of an associated trait with the bilateral symmetry found in that genus.

http://www.paleoportal.org/index.php?globalnav=fossil_gallery&sectionnav=search&taxon_id=55&state_id=&period_id=&assemblage_id=&last_section=search&p=5

http://www.google.com/images?q=Zaphrentis&btnG=Search&hl=en&gbv=1&tbm=isch

And I see some crinoid plates from the calyx.

... and some brachiopods, maybe of the order Spiriferida. The wide hinge lines (wing-like hinge line). are tip-offs about Spiriferida.

http://www.google.com/images?q=Spiriferida&btnG=Search&hl=en&gbv=1

http://en.wikipedia.org/wiki/Spiriferida

A person familiar with this exact formation may be able to cook my vague classifications down to more narrow classifications.

I like that you are using this material to excite kids about paleontology. Thank you for doing that.

They seem to have a lot of klinging limestone, and that might easily clean off with vinegar and toothbrush, exposing more features.

Edited November 1, 2014 by tmaier

[erose]

The round balls are the sponge Girtyocoelia. There are at least two species in the TX Pennsylvanian. Some of the slender but lumpy stems may be Fissispongia, another sponge. The rugose corals are Lophophyllidium. Again a couple of possible species within that genus. Couple of the brachiopods appear to be Chonetina, but there are a bunch of very similar genera to choose from and they would need to be sorted out a bit.

That may be bit closer on the IDs but the photos are only sort of clear enough. There are some great books for identifying our Texas Pennsylvanian material available to collectors. I don't have time to write them up now but a google search will reveal a handful specific to Texas. and there are some good ones on New Mexico that overlap nicely as well.

Edited November 1, 2014 by erose

[tmaier]

round balls sponge Girtyocoelia

http://www.google.com/images?q=Girtyocoelia&btnG=Search&hl=en&gbv=1

slender but lumpy stems may be Fissispongia, another sponge

http://www.google.com/search?q=Fissispongia&btnG=Search&hl=en&gbv=1&tbm=isch

rugose corals are Lophophyllidium

http://www.google.com/images?q=Lophophyllidium&btnG=Search&hl=en&gbv=1

brachiopods appear to be Chonetina

http://www.google.com/search?q=Chonetina&btnG=Search&hl=en&gbv=1&tbm=isch

[RyanNREMTP]

Nice finds. One of the DPS books on the Pennsylvanian age fossils is a great resource to have.

[Missourian]

Wow. Sponge-fest!

[LanceH]

A good old reference that has the same stuff as Texas Pennsylvanian is "The Fauna of the Wewoka Formation"

http://pubs.usgs.gov/bul/0544/report.pdf

Google image search is not really the best choice for IDs.

Everyone should build a collection of good references old and new.

Edited November 2, 2014 by LanceH

[crinoid1]

That is some seriously rich matrix, and quite a high percentage of sponges! Very cool

Gabe

[silverphoenix]

Thank you for the IDs! Had no idea they were sponges--must have been pretty odd looking when they were alive. If anyone wants to trade for some of this matrix, let me know!

[tmaier]

Had no idea they were sponges--must have been pretty odd looking when they were alive.

My mind immediately dismissed the "lumpy stems Fissispongia" as crinoid stems, in a split second and without even a thought. That is why I suggested cleaning them up. It would have become obvious they were not crinoids when it is discovered they couldn't be cleaned up.

The first sponges I found here in Florida I thought were burrow in-fills, because they had blobby shapes with no preserved parts. I tried cleaning one to only find that they had not hard part preserved. I accidentally destroyed a couple of them, but it helped understand them.

Edited November 3, 2014 by tmaier

[BobWill]

There are two similar sponges from there. Yours are Girtyocoelia as erose said. There is also a Girtycoelia (without the first "o"). Some of yours have a stem poking out one or both sides. This attached it to another ball in a long string which presumably protruded up from the seafloor. Girtycoelia lacked the stem and the balls attached directly to each other.

[JustPlainPetrified]

It's already been said...very rich material! Thanks for sharing.