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Swatara Gap State Park (1)


married2rick

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It was a beautiful sunny day here in PA so I took advantage of it by cracking open some rocks I found earlier this year at Swatara Gap State Park.

Pics 1 & 2.

I'm thinking this is part of a Greenops. Both cast and mold shown. One pic taken in sunlight and one in shade.

My question is, is this the head with eyes showing? It's at an angle where I can't quite figure it out.

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I know this one is a Greenops. (well, I think is more accurate, I'm trying...)

Let's start over... Is this a Greenops?

Pic 2.

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This one really has me confused. The part of the fossil that is detached reminds me of the stuff a broom is made of. (It's not flexible though).

It's just odd that it fell off when I split the rock.

Pic 4 & 5.

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It's really tough to do a Google search on something you don't know the name of...

I tried octagon star fossil and that led me to a Echinoderm but couldn't find any images that match my pic.

Any ideas?

Pic 6

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I call these death beds.

This one l found at Seven Stars. (Mahantango Formation)

What is the scientific name of this phenomenon?

Pic 7.

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And I just thought I'd share this pic of the baby Horseshoe Crab that I found this summer at the beach (Lewes, De). They seem so prehistoric to me.

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The trilobites are from the Middle Devonian. The Martinsburg Fm is Upper Ordovician.

Instead they must be Mahantango Fm trilobites: Greenops & Eldredgeops (=Phacops).

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This is my only swatara gap fossil. I've had this one for over 50 years. I lived in S. calif then, never even been to penn.

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Pics 4 and 5 look like a scaphopod. But I don't know anything about that site, so take that with a grain of salt.

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PRK

Oh my gosh, it's gorgeous!

Your 50+ yr old Trilobite is the reason I have very sore, cut, poked, pierced 50 year old fingers & hand! Lol, I'm getting a much later start than you but that's still the prize I got my eye on!!

What kind is that?

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Piranha - hmmm, I must have gotten that rock from Seven Stars and got it mixed up with my Swatara rocks. But I thought the ones with the ruffled frilly "skirt" were from Swatara. . .

Can someone recommend a good site that I can read/learn about these two locations and what all they produce? I feel even less knowledgeable than I did an hour ago. Lol, I just want to learn and move forward, not backwards, lol.

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Piranha - I thought the dekinyla was from mahantango and Greenops from swatara. Do I have it backwards?

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Scott is right on the money - the first trilo is an Eldredgeops, and the second one is a Greenops pygidium.

Pics 4 and 5 Show a Rugose or "horn" coral.

The "star" is actually a crinoid columnal, or section of stem.

Death assemblage, or "Hash" plate, are the terms we use to describe the kind of plates like yours from Seven Stars.

PRK's trilobite looks to be a Cryptolithus trilobite.

Cool finds. :)

Also,... the horseshoe crab is the closest living relative to trilobites. ;)

Regards,

PS- Google "Mahantango Formation Pennsylvania PDF", and try to read everything you can that comes up.

IF you need assistance, you could try to PM forum member Shamalama, as he is very familiar with the Mahantango formation.

This is his blog.

    Tim    -  VETERAN SHALE SPLITTER

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"In every walk with nature one receives far more than he seeks."

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The Eldredgeops in the first photo looks like it might be a complete enrolled one. It may be worth your while to see if you can dig it out and expose it better. Most of the ones I've found where the the cephalon and thorax are attached turned out to be complete. Good luck. By the way, the bedrock in Swatara Gap State Park as far as I know is Middle Devonian Mahantango Formation. I read that rock from a nearby road cut of fossiliferous Ordovician Martinsburg shale was dumped there for collectors, but almost all of it has long since been collected and removed.

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I'm still a little bit confused..... lol, by now you must all know that I am much more than just "a little" confused!

I thought I read one reply say that the Seven Stars location is Middle Devonian and of the Mahantango Formation which produces Greenops & Eldredgeops (both aka Phacops)

And another reply says that the bedrock in Swatara Gap State Park is also Middle Devonian and Mahantango Formation.

So, are both the Seven Stars & the Swatara Gap locations Mahantango Formations?

I read somewhere that someone linked the Swatara Gap location with the Martinsburg formation. Or am I wrong there?

Fossildude19 - I will print out and read the PDF you suggested tonight. Hopefully it will answer all these questions and more. :wacko:

I really appreciate everyone's patients with me, please know I really am giving this 100% effort. The real question here is, can an old dog really learn a new trick? Time will tell. (looking for an emoticon of a happy face pulling it's hair out, that one would be me, lol)

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Here is an excellent list of references with Pennsylvania fossils / geology / stratigraphy.
The Pennsylvania Geological Survey bulletins are all available for free download: LINK
 
Collie, George Lucius (1903)
Ordovician Section near Bellefonte, Pennsylvania. Description of New Species.
Geological Society of America Bulletin, 14:407-420
 
Stose, George Willis & Stose, Anna Jonas (1923)
Ordovician Overlap in the Piedmont Province of Pennsylvania and Maryland.
Geological Society of America Bulletin, 34:507-524
 
Stose, George W. (1930)
Unconformity at the Base of the Silurian in Southeastern Pennsylvania.
Geological Society of America Bulletin, 41(4):629-658
 
Swartz, Charles K.; Swartz, Frank M. (1931)
Early Silurian Formations of Southeastern Pennsylvania.
Geological Society of America Bulletin, 42(3):621-662
 
Willard, Bradford & Cleaves, Authur B. (1933)
Hamilton Group of Eastern Pennsylvania.
Geological Society of America Bulletin, 44(4):757-782
 
Swartz, Frank McKim (1934)
Silurian Sections Near Mount Union, Central Pennsylvania.
Geological Society of America Bulletin, 45(1):81-134
 
Willard, Bradford (1935)
Hamilton Group of Central Pennsylvania.
Geological Society of America Bulletin, 46(2):195-224
 
Swartz, Frank McKim (1935)
Relations of the Silurian Rochester and McKenzie formations near Cumberland, Maryland, and Lakemont, Pennsylvania.
Geological Society of America Bulletin, 46(8):1165-1194
 
Willard, Bradford (1935)
Portage group in Pennsylvania.
Geological Society of America Bulletin, 46(8):1195-1218
 
Willard, Bradford (1935)
Hamilton group along the Allegheny Front, Pennsylvania.
Geological Society of America Bulletin, 46(8):1275-1290
 
Willard, Bradford (1937)
Tully limestone and fauna in Pennsylvania.
Geological Society of America Bulletin, 48(9):1237-1256
 
Willard, Bradford & Cleaves, Arthur B. (1939)
Ordovician-Silurian relations in Pennsylvania.
Geological Society of America Bulletin, 50(7):1165-1198
 
Swartz, Charles K. & Swartz, Frank M. (1941)
Early Devonian and late Silurian formations of southeastern Pennsylvania.
Geological Society of America Bulletin, 52(8):1129-1192
 
Willard, Bradford (1943)
Ordovician clastic sedimentary rocks in Pennsylvania.
Geological Society of America Bulletin, 54(8):1067-1122
 
Howell, B.F. (1943)
New Upper Cambrian Faunas from Pennsylvania.
Geological Society of America Bulletin, 54:1831
 
Craig, Lawrence Carey (1949)
Lower middle ordovician of south-central Pennsylvania.
Geological Society of America Bulletin, 60(4):707-779
 
Willard, Bradford (1955)
Cambrian contacts in eastern Pennsylvania.
Geological Society of America Bulletin, 66(7):819-834
 
Sando, William J. (1958)
Lower Ordovician Section Near Chambersburg, Pennsylvania.
Geological Society of America Bulletin, 69(7):837-854
 
Willard, Bradford (1932)
Devonian Faunas in Pennsylvania.
Pennsylvania Geological Survey, Fourth Series, Bulletin G4:1-43
 
Whitcomb, Lawrence (1932)
Correlation of Ordovician limestone at Salona, Clinton county, Pennsylvania.
Pennsylvania Geological Survey, Fourth Series, Bulletin G5:1-16
 
Willard, Bradford (1938)
A Paleozoic Section in South-Central Pennsylvania. Pennsylvania.
Pennsylvania Geological Survey, Fourth Series, Bulletin G8:1-36
 
Willard, Bradford (1938)
A Paleozoic section at Delaware water gap. Pennsylvania.
Geological Survey, Fourth Series, Bulletin G11:1-35
 
Willard, Bradford (1939)
The Devonian of Pennsylvania.
Pennsylvania Geological Survey, Fourth Series, Bulletin G19:1-481
 
Willard, Bradford (1939)
Middle and Upper Devonian. In: Willard, B. The Devonian of Pennsylvania.
Pennsylvania Geological Survey, Fourth Series, Bulletin G19
 
Swartz, Frank M. (1939)
Keyser Limestone and Helderberg Group. In: Willard, B. The Devonian of Pennsylvania.
Pennsylvania Geological Survey, Fourth Series, Bulletin G19
 
Cleaves, Arthur B. (1939)
Oriskany Group. In: Willard, B. The Devonian of Pennsylvania.
Pennsylvania Geological Survey, Fourth Series, Bulletin G19
 
Chow, Minchen Ming (1951)
The Pennsylvanian Mill Creek Limestone in Pennsylvania.
Pennsylvania Geological Survey, Fourth Series, Bulletin G26:1-36
 
Howell, B.F. (1957)
Upper Cambrian fossils from Bucks County, Pennsylvania.
Pennsylvania Geological Survey, Fourth Series, Bulletin G28:1-28
 
Thompson, Richard Rogers (1963)
Lithostratigraphy of the Middle Ordovician Salona and Coburn formations in central Pennsylvania.
Pennsylvania Geological Survey, Fourth Series, Bulletin G38:1-154
 
Ellison, Robert L. (1965)
Stratigraphy and Paleontology of the Mahantango Formation in South-central Pennsylvania.
Pennsylvania Geological Survey, Fourth Series, Bulletin G48:1-298
 
Lees, John A. (1967)
Stratigraphy of the Lower Ordovician Axemann Limestone of central Pennsylvania.
Pennsylvania Geological Survey, Fourth Series, Bulletin G52:1-79
 
 
 

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Excellent list, Scott!

Thanks for compiling it.

Regards,

    Tim    -  VETERAN SHALE SPLITTER

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__________________________________________________
"In every walk with nature one receives far more than he seeks."

John Muir ~ ~ ~ ~   ><))))( *>  About Me      

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I'm still a little bit confused..... lol, by now you must all know that I am much more than just "a little" confused!

I thought I read one reply say that the Seven Stars location is Middle Devonian and of the Mahantango Formation which produces Greenops & Eldredgeops (both aka Phacops)

And another reply says that the bedrock in Swatara Gap State Park is also Middle Devonian and Mahantango Formation.

So, are both the Seven Stars & the Swatara Gap locations Mahantango Formations?

I read somewhere that someone linked the Swatara Gap location with the Martinsburg formation. Or am I wrong there?

Fossildude19 - I will print out and read the PDF you suggested tonight. Hopefully it will answer all these questions and more. :wacko:

I really appreciate everyone's patients with me, please know I really am giving this 100% effort. The real question here is, can an old dog really learn a new trick? Time will tell. (looking for an emoticon of a happy face pulling it's hair out, that one would be me, lol)

M2R,

OK. A few things.

Greenops and Eldredgeops are different trilobite genera. (only Eldredgeops was named Phacops. The name was changed not too long ago from Phacops to Eldredgeops)

Swatara Gap, along route 81, a bit south-east of Swatara State Park, was a fossil site that was over collected, and threatened to undermine the highway : that was Martinsburg Formation, Ordovician in age. (now closed)

Before they closed the site, as they were removing the fossiliferous rock, they dumped a large pile of the debris from that project into an area within Swatara State Park. My understanding is that pile is long gone, and not much to be found where they dumped it.

Now, within the Swatara State Park, there are exposures of the Devonian Mahantango formation.

So there was Ordovician rock dumped there, (now long gone) but the area outcrops immediately within the park are Devonian aged. ;)

Make sense??

Also, found this.

Interesting Lancaster LINK.

Hope this clarifies the issue for you.

Regards,

    Tim    -  VETERAN SHALE SPLITTER

   MOTM.png.61350469b02f439fd4d5d77c2c69da85.png      PaleoPartner.png.30c01982e09b0cc0b7d9d6a7a21f56c6.png.a600039856933851eeea617ca3f2d15f.png     Postmaster1.jpg.900efa599049929531fa81981f028e24.jpg    VFOTM.png.f1b09c78bf88298b009b0da14ef44cf0.png  VFOTM  --- APRIL - 2015  

__________________________________________________
"In every walk with nature one receives far more than he seeks."

John Muir ~ ~ ~ ~   ><))))( *>  About Me      

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The pentagonal crinoid ossicle (pic 6) is very interesting and good preserved, looks to very appropriate to Iocrinus subcrassus : http://www.drydredgers.org/crinoids_disparida.htm#Cincinnaticrinus_Lookalikes

" We are not separate and independent entities, but like links in a chain, and we could not by any means be what we are without those who went before us and showed us the way. "

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AWESOME Tim!!! I live so close to all the sites mentioned in the "Interesting Lancaster Link"!!

And yes, your reply puts me another step closer to understanding. Very much appreciated, thank you!

And PIRANHA, saying thank you just doesn't seem good enough for that list of references!! I will be checking them out tonight and tomorrow! This is VERY exciting!!

And abyssunder, I checked out your link and and I googled Iocrinus subcrassus I haven't found any images that look like my fossil but much of what I did find from your reply indicates you put me on the right path!!

JefferyP, thanks for you comment "The Eldredgeops in the first photo looks like it might be a complete enrolled one. It may be worth your while to see if you can dig it out and expose it better. Most of the ones I've found where the the cephalon and thorax are attached turned out to be complete." I really think it is time for me to invest in the right tools so that I can properly expose it vs ruining this Eldredgeops (my first!) by using my dental tools, hammer & chisel. lol

I feel like I just won an emmy or something with the way I am thanking people. Nah, getting educated like this by people who really want to teach feels way better than winning any silly trophy!!!

Seriously, thanks EVERYONE for caring enough about this stuff to share it. Maybe, just maybe, some day I will be a teacher on TFF! :fingers crossed:

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...Maybe, just maybe, some day I will be a teacher on TFF! :fingers crossed:

You already are! We host up to 45,000 unique visitors a month, and these unregistered 'students' constitute your 'class'.

Think about it: how many now know more, because you asked the questions? Teaching isn't about knowing, it's about helping others learn. :)

"There has been an alarming increase in the number of things I know nothing about." - Ashleigh Ellwood Brilliant

“Try to learn something about everything and everything about something.” - Thomas Henry Huxley

>Paleontology is an evolving science.

>May your wonders never cease!

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