Winter Hunt at the Ammonite Beach, Lake Texoma

[Mikrogeophagus]

Back in January I decided to check out the Ammonite Beach at Lake Texoma for the first time. The site is well known for its giant Duck Creek ammonites that can be found scattered all over the shoreline. The weather was surprisingly not that bad despite it being the winter. The water level was quite low and there was plenty of good ground to search along. During my time there, I had some success in finding my own ammonites which gave me an excuse to finally put my rock hammer to use. I stumbled upon some echinoids, but none of them were in all that great of condition, so I might need to head back again in the future to solve that issue. Lastly, there were some interesting fossil finds of stuff I didn't expect to be there (more on this later).

 

A lot of the ammonites that come out of Texoma are encased in a decent amount of rock/mud. I have very little experience in any sort of prep work, so cleaning them up was my chance to try something new. My tools were a bit primitive (hammer and kitchen ice pick which got destroyed), but I managed to clean up an ammonite without breaking it for the first time. I didn't think to take a before pic, but the whole face was covered in hard matrix much like on the reverse side.  

Unfortunately, I made a lot of white scratch marks on it, but I'm mostly just relieved that it came out in one piece. Apologies if this hurts the eyes of any more experienced ammonite preppers reading this . It was a long process and I decided against cleaning up both sides as that seemed too risky of a prospect. I'm fairly certain it is one of those Mortoniceras given the pointy tubercles covering it. Once I finished that, I watched a Lake Texoma video made by "The Fossil Fiend" on YouTube. Even though this was a few weeks after my trip, my exact ammonite showed up on his video! I couldn't believe my eyes when he was pointing right at it as shown in the screen grab above. It's a perfect match to my second pic. What a funny coincidence!

 

My brother and I hauled up a much larger ammonite as well. I'm going to try harder to not scratch this one. I managed to get some work done before winter break ended, but there's still a long way to go. This is gonna be a fun summer project.

 

Beyond ammonites, I came across a plethora of smaller finds that I view to be just as interesting. Below is an overview of the coolest ones:

 

'A' and 'B' appear to be Leptostyrax macrorhiza? and Cretolamna appendiculta? respectively. I heard that sharks teeth were rarely found at Texoma so coming out with two of them in a single hunt was really exciting. Additionally, I found a piece of what I think is some sort of Cretaceous fish tooth (C). It's black and fairly reflective. A cross section of the tooth is like a football in shape. In other words, there are two edges that run opposite of one another from top to bottom while the rest is rounded. I tried to capture a photo of this, but had some difficulty. Here are some closeups:

 

Something very unexpected was the large amount of pyritized microfossils to be found all over the shoreline, interspersed with the ammonites and echinoids. I had never heard of pyritized microfossils being at Texoma, so I was a bit confused as to why they were there and in such great numbers. It really did feel like I was back in the Waco Pit. I found pyritized ammonites, bivalves, and gastropods. I'm curious if anyone knows what formation they're from. I am under the impression that the whole area is Duck Creek formation, so is that simply what happens to smaller shelled fauna in that layer? The pyritized ammonite 'E' I have below somewhat resembles Mortoniceras, but I'm not sure if they come from vastly different points in time. 'F' reminds of me of a miniature Oxytropidoceras. 'D' is a pyritized heteromorph ammonite. I don't think heteromorph ammonites are known to come out of the Duck Creek, at least in larger form, which makes me think these pyrite fossils are from a different period. Really curious to hear what you guys think of all this! I covered them in wax to prevent degradation. That made it a little harder to pick out details, especially through a camera unfortunately. Here's some closeups:

 

The last handful of fossils are just a sample of the fish verts and tiny oysters I came across:

 

All in all, it was a fun trip - very different from the other sites I have been to. After learning of the huge presence of pyritized microfossils there, I get the impression that it's like having two sites in one; the Waco Pit and the more traditional Texoma famous for its beautiful ammonites/echinoids. Paired with its proximity to Post Oak Creek, I will definitely being taking more drives up there in the future when I'm back in DFW. As usual, let me know if you would like any additional close ups. Thanks for reading!

 

[Ludwigia]

Thanks for the report. You did a good job on that ammo considering you only had an ice pick at your disposal.

[fossilhunter21]

Cool trip! Those are some very nice finds.  BTW I think you did a good job on that first ammonite and the one you are working on is coming out good, especially since you don't have a lot of experience, and you were using a hammer and an ice pick. 

 

-Micah

Edited April 9, 2022 by fossilhunter21

[Tidgy's Dad]

Great finds and a pretty good job on that ammonite too

Thanks for sharing. 

[DPS Ammonite]

I think that I remember a pyritized micromorph fossil zone with Plicatula and ammonites in the lake side cliff of the Lake Texoma spillway. North Texas Fossils places it in the upper part of the Duck Creek Formation:

 

http://northtexasfossils.com/duckcreek.htm

[Mikrogeophagus]

Thanks everyone for the positive feedback on the prep!

 

@DPS Ammonite That's really interesting. I guess the Duck Creek is more complicated than I expected. I remember hearing in a video that the reason there are pyritized microfossils in the Waco Pit is because it got cut off as an inland sea, lowering the local oxygen levels. Some sort of bacteria present in these anoxic conditions at the time caused for the fossils to frequently pyritize. I wonder if a similar event took place to form these microfossils in the Duck Creek.

[Bill Hoddson]

Just read this post - Thank you for telling me about it earlier.  It's on my way home to Michigan, and should be just the distraction I need right now!

 

If I find anything, I'll remember to let you know

[Bill Hoddson]

My trip to the boat ramp neat the Denison Dam/Lake Tacoma wasn't terribly productive, as far as "trophies" to take home, but for a rookie looking for ammonites wasn't bad.

 

It took me a bit to figure out what to look for, and where.  Once that was settled, I did find a beautiful exterior mold in a 4x4ft boulder, and a larger internal cast nearby.  I was able to find a couple partials that I could bring home.

[Mikrogeophagus]

I'd say you did a good job. That piece looks like it would be hard to spot! Unfortunately, I don't think the weather has been conducive for lots of fossils. Always fun to explore a new site nonetheless!