Deer Lake Trip_Trilobites, Crinoid Tentacles And Shells

[hitekmastr]

We keep saying we're too busy this Fall for more fossil trips but managed to squeeze in a half day trip to Deer Lake (PA) on Saturday, Oct. 6. We spent several hours exploring and sorting through the Mahantango formations there on Highway 61. Mostly I excavated some pieces out of the softer shale formations that were dampened by recent rains that made it easier, and Nancy cracked open the larger rocks - nothing earth-shaking, but an interesting trip.

We found trilobite, shells, gastropods, cephalopod fragments and possibly a faint impression of crinoid "tentacles."

One of our goals was to collect some shell assemblages that we can display as small sculptures (we drill holes in the bottom, insert stained wooden dowels, and insert the other end of the dowels into small wooden "trophy bases" we get from a craft shop. Here are some of our "assembage" pieces - none are cleaned yet so these are exactly as we brought them home:

Our second goal was to verify that there are trilobites here because we keep reading about trilobites found here - so we accomplished that goal although what we found are mostly fragments. One piece may yield more after we process it a bit:

After extracting some shells and trilobite fragments - which was fairly hard work, chopping out reasonably large sections from the wet crumbly shale, we spent some time inspecting the rubble on the steep slope immediatley behind Michael B's Restaurant. We found a section that had a lot of gastropods and took home a few pieces - here is an example with two gastropods:

I chopped into some very hard shale from the far slope behind the "parking lot" area and from the shale, this looked like it may have been deeper water with fewer fossils and it's my impression that there could be some larger fossils there but with hammer and chisel it's always hard to find very large Devonian fossils that may have lived in the deeper ocean bed but even if they are present, trying to find and extract them runs the risk of shattering them before you even know they are there. I didn't have that problem because I didn't find anything large but I'm always wary of finding something really big that gets ruined or winds up in pieces and has to be pieced back together like a jigsaw puzzle.

I pulled out the largest pieces I could excavate with hammer and chisel, and found lots of interesting oval shaped brown concretions in the grey shale, a few pieces of very large "tubes" that were a few centimeters in diameter, very few small fossils and evidence of larger structures which gave me the sense that there might be larger fossils here.

Then I pulled out what looked like the pattern of soft tissue from a crinoid or other sea creature. If you look closely at the image, in the center of the photo, you can see what looks like a small piece of shell with tentacles flowing up and to the right. Then, there seems to be another impression of tentacles coming in from the top right of the photo - those larger tentacles are flowing from the left edge of the photo, toward the center. It is hard to see these unless the shale is wet. A friend of mine found a fully articulated crinoid calyx recently, so I remain hopeful of finding something like that but for now these impressions are the closest we've come:

Another interesting find is a three dimensional fossil that we haven't identified yet - ideas welcome:

Deer Lake is a bit more than an hour from our home so the drive is easy but finding time for fossil trips is difficult given our busy schedules and projects at work. We do have quite a few fossils that we need to examine more closely and "process" which is our winter project. Some fossils that are not easy to identify or confirm require some detailed grinding and I plan to use a Dremel for that although I haven't done this before so will probably ruin a few before I get the hang of it.

We have created some displays using Riker mounts - I like the 12x16 in 1 or 2 inch depths and found that buying them online by the case is cheaper than one at a time. Nan and I also agreed to do a display booth on Carboniferous coal swamps with some of our fossils at the annual Fossil Fair of the Delaware Valley Paleontological Society next Spring.

Edited October 7, 2012 by hitekmastr

[Fossildude19]

Hi Michael,

Quite a bunch of nice finds again. I really like your gastropods.

I think that your Trilobite2 pic may actually be a bryozoan, though. Taeniopora exigua.

Thanks for posting your finds. I always enjoy looking at your treasures.

Regards,

Edited October 7, 2012 by Fossildude19

[Trevor]

Nice finds!

[hitekmastr]

Hi Michael,

Quite a bunch of nice finds again. I really like your gastropods.

I think that your Trilobite2 pic may actually be a bryozoan, though. Taeniopora exigua.

Thanks for posting your finds. I always enjoy looking at your treasures.

Regards,

Thanks - I'll carve away some of the shale to confirm your diagnosis - you think the ridge below the pimpled section is part of the wall of the bryozoan?

[Fossildude19]

Thanks - I'll carve away some of the shale to confirm your diagnosis - you think the ridge below the pimpled section is part of the wall of the bryozoan?

I think so.

Regards,

[hitekmastr]

Hi Michael,

Quite a bunch of nice finds again. I really like your gastropods.

I think that your Trilobite2 pic may actually be a bryozoan, though. Taeniopora exigua.

Thanks for posting your finds. I always enjoy looking at your treasures.

Regards,

Since you like the gastropods, I wasn't going to include these, but this is another interesting find from the trip - on one side of the rock it is a perfectly round sphere which is the first thing I saw when I cracked it out of the substrate - on the other side, the rest of the fossil is revealed but I'm not sure what it is. It looks like an internal mold. Here are the images - not sure if this is "gastro-" or "cephalo-" - any ideas?

[Fossildude19]

Michael,

That may be some specie of Bellerophontid gastropod. Maybe an internal mold of Bucanopsis?

I know Dave (shamalama) has found some of those in the Mahantango.

Regards,

[piranha]

Trilobite photos 2 and 3 are more Dipleura pieces

Photo 2 is the anterior portion of the pygidium with articulating half-ring and articulating furrow. LINK

Photo 3 is a thoracic tergite with articulating half-ring and articulating and pleural furrow.

[Bev]

Great Finds!

[Fossildude19]

Trilobite photos 2 and 3 are more Dipleura pieces

Photo 2 is the anterior portion of the pygidium with articulating half-ring and articulating furrow. LINK

Photo 3 is a thoracic tergite with articulating half-ring and articulating and pleural furrow.

I stand corrected.

Thanks Scott.

The image helps to clarify.

Regards,

[hitekmastr]

Trilobite photos 2 and 3 are more Dipleura pieces

Photo 2 is the anterior portion of the pygidium with articulating half-ring and articulating furrow. LINK

Photo 3 is a thoracic tergite with articulating half-ring and articulating and pleural furrow.

Well, this is certainly encouraging! We did a lot of "fracking" of shale in our special spot at Deer Lake, to try to find where the trilos might be lurking - this justifies our hard work and confirms that there are Dipleura there and our spot is worth excavating further.

Piranha, your diagnosis and the image link you included will help me convince Nan to return to Deer Lake to see what else we can find. Thanks...we might not have gotten back this Fall but we really like Dipleura so this is a strong incentive to hit the spot again.

Edited October 8, 2012 by hitekmastr

[Bullsnake]

Can't wait to see your sculpture pieces. That Spirifer brach is sweet!

[hitekmastr]

Can't wait to see your sculpture pieces. That Spirifer brach is sweet!

Here is the finished sculpture on the Fossil Forum: http://www.thefossilforum.com/index.php?/topic/36269-devonian-display-idea-fossils-on-a-rod/

[Shamalama]

Your unknown 3-d fossil is a pelecypod called Grammysiodea. Hard to tell what the Gastropods are from the pics but I think your "soft tissue" is some mineral staining.

[hitekmastr]

Your unknown 3-d fossil is a pelecypod called Grammysiodea. Hard to tell what the Gastropods are from the pics but I think your "soft tissue" is some mineral staining.

Thanks for the ID - this is great. At Deer Lake there is a section that has mostly gastropods, spread out quite a bit but easy to extract. Actually, the place where we spend most of our time is a small section about the size of two bathtubs that has a concentration of death assemblages. That's where most of the shells and trilo bits came from - expect to revisit that spot with a pick ax to see if I can pull out larger pieces. It's very solid and tricky to extract because the best fossils are embedded in solid rock. Waiting for a weekend when Nan and I are free - since it's only an hour from our house. ALSO...Nan suspects that we are looking in one site at Deer Lake but she has a sense that there are several good sites in the vicinity but we may not have discovered or become aware of them yet since we focus on one spot.