My Mazon Creek Finds

[RCFossils]

I took another look after JDP’s comments and I can see why he is thinking this might be a tetrapod.

Please let us know if you have a chance to examine this in person.

A tetrapod would be a wonderful conclusion to an already successful collecting year.

[snails]

This looks like a larval lungfish to me, minus the pectoral and pelvic appendages which may be present in the fossil but are not apparent in the photos. Look up larval lungfish in google images and some are great matches. Look like some of the larval extant lungfishes I've seen.

[jdp]

5 hours ago, snails said:

This looks like a larval lungfish to me, minus the pectoral and pelvic appendages which may be present in the fossil but are not apparent in the photos. Look up larval lungfish in google images and some are great matches. Look like some of the larval extant lungfishes I've seen.

 

Not everything IDed as lungfish actually is, so take internet IDs (and even museum IDs) with a grain of salt. There are a few things I can point to that suggest this is not a lungfish, though. Notably, there are a few vertebral centra beginning to ossify behind the skull (absent in post-Devonian lungfishes) and a few bones of the skull that are inconsistent with a lungfish identification, notably a pretty conspicuous jugal. I would also expect to see an ossified operculum in a juvenile lungfish of this size. 

[jdp]

There's also something that looks like a femur.

[deutscheben]

I have had a few more vague finds split from my Chowder Flats material.

 

First is this one, it seems like a kind of exploded worm of some sort?

 

 

These next two could be coprolites or trace fossils, or maybe nothing?

 

 

 

And this one is a few different pieces of bark or worn plant material.

 

 

Finally, this last one came from the largest concretion I have found from the site, a very rounded one nearly 2 inches thick. It split into a number of thinner layers, mostly filled with small bits of plant material, but one split revealed this intriguing shape:

 

 

The narrow band that runs across the concretion is about 2 mm wide, and my first guess is that it is some type of worm. I’m not really sure what type though- it has no bristles or identifying features that would mark it as a polychaete, and Archisymplectes is not supposed to have any segmentation or ornamentation. 
 

It’s vague enough that it could certainly be something else, though. Here are some magnified images:

 

 

[stats]

On 1/2/2022 at 4:57 PM, RCFossils said:

I took another look after JDP’s comments and I can see why he is thinking this might be a tetrapod.

Please let us know if you have a chance to examine this in person.

A tetrapod would be a wonderful conclusion to an already successful collecting year.

There is a bunch more detail there when I zoomed in.  Exciting!

 

Cheers,

Rich

 

[RCFossils]

Not sure what this is.

It is possibly an undescribed annelid worm but cannot say for sure.

There is also a possibility that it is some type of unusual trace fossil.

[deutscheben]

Thanks @RCFossils! 
 

I have had some more flora split from the river in the last week. (First two backgrounds are 1 inch grids, third is 1 cm). Please let me know if I’m off on any IDs.

 

First was this colorful bit of Cordaites leaf:

 

Next is this somewhat faint piece including the two common ferns Crenulopteris and Diplazites.

 

 

Finally, this is a nice single Diplazites pinnule, a very common find but the highest quality one in my collection. 

 

[connorp]

4 minutes ago, deutscheben said:

Finally, this is a nice single Diplazites pinnule, a very common find but the highest quality one in my collection. 

 

Nice one!

[Mark Kmiecik]

Nice and interesting finds.

[deutscheben]

As the opening of the fossil collecting season at Pit 11/Mazonia-Braidwood State Fish and Wildlife Area approaches, I find myself getting down to the end of my unopened concretions from last season. 
 

I have had a few notable finds in the last week from both my Chowder Flats and Mazon River  buckets. First are a few common flora items from the river- the tip of a Macroneuropteris pinnule:

 

 

And a Calamites twig:

 

 

I also found a fantastic teeny tiny fish scale (5 mm long) in a concretion almost as big as the one just above. I’m not sure what type of fish it belongs to, any ideas?

 

 

 

Finally, from my Chowder Flats material I found another diminutive delight, what I believe is a Palaeocaris typus shrimp. Shrimp have been a rare find for me from this site, so this was a nice surprise to have a more or less complete one split. The shrimp is about 15 mm long. 
 

 

 

[connorp]

2 hours ago, deutscheben said:

As the opening of the fossil collecting season at Pit 11/Mazonia-Braidwood State Fish and Wildlife Area approaches, I find myself getting down to the end of my unopened concretions from last season. 
 

I have had a few notable finds in the last week from both my Chowder Flats and Mazon River  buckets. First are a few common flora items from the river- the tip of a Macroneuropteris pinnule:

 

 

And a Calamites twig:

 

 

I also found a fantastic teeny tiny fish scale (5 mm long) in a concretion almost as big as the one just above. I’m not sure what type of fish it belongs to, any ideas?

 

 

 

Finally, from my Chowder Flats material I found another diminutive delight, what I believe is a Palaeocaris typus shrimp. Shrimp have been a rare find for me from this site, so this was a nice surprise to have a more or less complete one split. The shrimp is about 15 mm long. 
 

 

 

I think the fish scale is coelacanth. Great find!

 

Here is a similar looking one I collected in the Mecca Quarry Shale.

 

Edited February 17, 2022 by connorp

[Mark Kmiecik]

Nice finds. The leaf looks like M. macrophylla, no "hairs", pointy tip. 

[deutscheben]

Thanks for the suggestions @connorp and @Mark Kmiecik. 
 

Yesterday I had an exciting find from my Mazon River concretions. At first I couldn’t tell what it was exactly- it was clearly bone, but I wasn’t sure what kind since only a small part was exposed. (The part shown below is about 10mm wide)

 

 

As you can see, there was a large flake of loose matrix above the fossil, which I was able to work loose. Once I did that, it became clear what I was looking at.

 

 

It was the root of a shark tooth! At this size, I believe the generally accepted ID would be Orthacanthus sp.

 

There were further cracks propagating across the surface of the concretion, so I looked to see if there were any pieces I could remove (delicately) to expose more of the tooth without causing the whole thing to come apart. So far I was able to pop off a small part to show the base of one cusp.

 

 

Looking at the outer edge of the concretion you can actually see where the tip of the cusp exits (as well as the crack that extends all the way around the concretion).

 

I am hopeful that with some careful prep  and some repair I can expose more of the tooth. 
 

Interestingly, the ESCONI fauna guide states that Orthacanthus teeth from Mazon Creek do not have serrations, while this one clearly does. (They can appear both ways in the genus as a whole) Any folks out there have other examples with serrations on them?

 

I can’t find that any scientific papers have been done about these type of teeth from this locale, either, so it looks like an area where more research is needed to really get a firm ID. 

 

[connorp]

1 hour ago, deutscheben said:

Thanks for the suggestions @connorp and @Mark Kmiecik. 
 

Yesterday I had an exciting find from my Mazon River concretions. At first I couldn’t tell what it was exactly- it was clearly bone, but I wasn’t sure what kind since only a small part was exposed. (The part shown below is about 10mm wide)

 

 

As you can see, there was a large flake of loose matrix above the fossil, which I was able to work loose. Once I did that, it became clear what I was looking at.

 

 

It was the root of a shark tooth! At this size, I believe the generally accepted ID would be Orthacanthus sp.

 

There were further cracks propagating across the surface of the concretion, so I looked to see if there were any pieces I could remove (delicately) to expose more of the tooth without causing the whole thing to come apart. So far I was able to pop off a small part to show the base of one cusp.

 

 

Looking at the outer edge of the concretion you can actually see where the tip of the cusp exits (as well as the crack that extends all the way around the concretion).

 

I am hopeful that with some careful prep  and some repair I can expose more of the tooth. 
 

Interestingly, the ESCONI fauna guide states that Orthacanthus teeth from Mazon Creek do not have serrations, while this one clearly does. (They can appear both ways in the genus as a whole) Any folks out there have other examples with serrations on them?

 

I can’t find that any scientific papers have been done about these type of teeth from this locale, either, so it looks like an area where more research is needed to really get a firm ID. 

 

Wow, two rare fish finds, very awesome! You must have been collecting at a good spot.

[TheRocksWillShoutHisGlory]

This tooth is spectacular.  I'm impressed with you prepping it out to expose it. From my understanding Orthacanthus has 2 pronged teeth, and the Mazon examples haven't had serrations, both of which is also unlike this one.  

 

I can't tell with the calcite, but this could be a Lingulid with a partial pedicle or trail from it.

On 1/6/2022 at 9:19 PM, deutscheben said:

 

[Mark Kmiecik]

 

There are several species in the genus Orthacanthus. You may have one that is identifiable.

 

From Wikipedia:

 

Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Chondrichthyes
Superorder:	Selachimorpha
Order:	†Xenacanthida
Family:	†Orthacanthidae Heyler and Poplin, 1989
Genus:	†Orthacanthus Agassiz, 1843
Species
Orthacanthus (Agassiz, 1843) Orthacanthus arcuatus (Newberry, 1856) [2] Orthacanthus buxieri (Heyler and Poplin, 1989) Orthacanthus compressus (Newberry, 1856) Orthacanthus donnelljohnsi (Johnson and Thayer, 2009) Orthacanthus gibbosus (Agassiz, 1843) Orthacanthus gracilis (Newberry, 1875) Orthacanthus milleri (Agassiz, 1843) Orthacanthus minor (Agassiz, 1843) Orthacanthus platypternus (Cope, 1884) Orthacanthus pustulosus (Agassiz, 1843) Orthacanthus texensis (Cope, 1888)

The larger teeth of Orthacanthus compressus and Orthacanthus texensis are differentiated by a more pronounced basal tubercle in O. compressus.^[6] The basal tubercle of a typical tooth file is on the apical button of the underlying tooth.^[7] The larger adult teeth of O. compressus have a wider rather than longer base, similar to O. texensis, and tend to have serrations on both carinae of each cusp, while the medial carinae of smaller adult teeth are not serrated.^[6] The juvenile teeth of O. compressus are longer than wide, have a thinner base, and lack serrations, similar to O. platypternus teeth.^[6]

[deutscheben]

In true Pit 11 fashion, my first concretion to split from this year’s batch was an Essexella:

 

 

I am down to my last 4 or 5 concretions each for both my Chowder Flats and Mazon River material.

 

I had a few more interesting things split from my Chowder Flats material. First is an addendum to a plant specimen I posted earlier. I noticed an additional crack on the side of the concretion so I tapped it, and when it split I found a squashed Achistrum sea cucumber.

 

 

 

 

Finally, I have no idea what this seemingly segmented piece is. A mystery worm? Some kind of arthropod? A coprolite? I tried prepping one end that seemed to go into the concretion but it didn’t reveal anything. Let me know if you have any ideas!

 

 

 

[Mark Kmiecik]

3 hours ago, deutscheben said:

 

Looks shrimpy to me.

[deutscheben]

My latest split from this year’s Mazonia-Braidwood finds is a fun one, my second Octomedusa pieckorum. This little jellyfish is not super well-preserved, but you can clearly see the bases of the 8 tentacles. 
 

[deutscheben]

In the 2 months since my last post, the only recognizable Pit 11 fossils I have had split are multiple Essexella and one very indistinct worm- not a good year for me so far, and with temps like we are seeing now I may not make it back out to the park again before September.
 

Thankfully I was able to collect some more Chowder Flats concretions earlier this year as well, and one split yesterday revealing this Annularia radiata:

 

 

 

[stats]

Very nice!

 

Cheers,

Rich

 

[deutscheben]

Today I have some very average examples of common fauna and flora. All three are from the Chowder Flats locale. 
 

First is a double Essexella asherae:

 

 

Next is a low-detail example of the fern Diplazites unita:

 

 

And finally, appropriate for the site, here is a somewhat squashed Aviculopecten mazonensis. 
 

 

Nothing spectacular, but I feel it’s important to share the average fossils as well as the stunning ones.

[Nimravis]

On 2/25/2022 at 11:46 AM, deutscheben said:

Interestingly, the ESCONI fauna guide states that Orthacanthus teeth from Mazon Creek do not have serrations, while this one clearly does. (They can appear both ways in the genus as a wh

Just saw this Ben, great find, congrats.

[deutscheben]

It’s been another quiet few months of freezing and thawing for me. The last of my Pit 11 and Chowder Flats concretions were blanks, and now I’ve started working on some new ones from the river. 
 

These have mostly produced flora, as expected. My nicest find so far is this dainty Annularia sphenophylloides.

 

 

 

I also found this Sphenophyllum emarginatum with microconchids on the leaves. 
 

 

 

And a decent Crenulopteris acadica.

 

 

I did find one tiny bit of fauna too, the common shrimp Acanthotelson stimpsoni. 
 

 

Edited September 4, 2022 by deutscheben
Updated ID