Texas Shark Tooth Extravaganza

[GPayton]

It's been over a month now since @Jared C and I found the Eagle Ford Xiphactinus. In the weeks that followed our discovery I was able to get in touch with the right people at Baylor University where I go to school and start to organize a retrieval project. Unfortunately I haven't been able to make it back to the site since then as all involved will have to wait for the wheels of bureaucracy to turn enough for us to have the proper permission necessary to return. So I was left with a problem: my first visit to the Eagle Ford turned out so well that I wanted nothing more than to go back, but I couldn't! Of course, that was just because I only knew of one exposure. And so I turned to more old literature in the hopes that I could locate another productive site the same way I had the first one. 

After many hours of reading papers that were filled to the brim with so much scientific jargon that they often went completely over my head, it seemed like I had finally struck gold when I found directions to a specific locality. Several days later I found myself with enough free time to make a scouting trip. 

The woods that I traveled through to get to the creek that was my ultimate destination were not making my job easy for me. Anyone who's spent even a little time outdoors in the eastern half of Texas knows that any given stretch of woods is about 80% brambles and thorns. This particular area was absolutely covered in them. I made slow progress - every fifteen minutes that passed would find me moving roughly the same number of feet. Eventually I got lucky and stumbled onto a trail through the thorns made by the local hogs. It's probably the only time I've ever been grateful for an invasive species! 

Following the trail led me to a steep bank and the creek I had been looking for. Peering over the ledge, I could see that the sides were lined with shale almost from top to bottom. All that shale had to mean fossils and so I wasted no time in making my way down to the creekbed. The paper I was referencing told me that I was within the Lake Waco and South Bosque formations of the Eagle Ford group, but it didn't take long for me to realize that there were probably others present as well. Massive slabs of limestone had fallen from the ledges at the top of the bank and littered the creekbed. Here's a picture of probably the biggest one I saw:
 

 

My best guess is that this was some of the nearby Austin Chalk making a surprise appearance. 

From there I made my way westward. Fragments and impressions of giant inoceramid bivalves were visible on almost every scrap of rock I passed. I was so focused on inspecting the broken pieces of shale and limestone I was picking my way through that I failed to notice the pack of wild hogs I had inadvertently cornered! The creek dead-ended just beyond a fallen log, behind which were the makers of the trail I had followed through the woods. A limestone ledge formed a now-dry waterfall and below it was a pool of stagnant water and mud that the local hogs were obviously using as a place to wallow and escape the Texas summer heat - I can't say I blame them! 
I made sure to give them enough space to escape up the side of the bank and once I was sure they were gone I moved to inspect the pit they had been so kind to leave me.

 

 

The shale I had been walking alongside further up the creek was exposed in all its many-layered glory here. For a mudhole used by a bunch of pigs it was surprisingly beautiful, and I found my breath briefly taken away when I got my first good look at it. Interpreting what I was seeing using the paper that had led me here proved to be a challenge at this point. At first I believed that everything below the waterfall ledge was the Lake Waco formation and everything above it was the South Bosque, but after a LOT of research since my first visit I'm now fairly confident in saying that almost everything I saw was just one particular member of the Lake Waco formation: the Cloice.

The first finds of the day were located on the right side of the picture above in a layer just above a bentonite seam and just below the thick layer represented by the waterfall ledge. See how fast you can figure out what they are:

 

 

The tooth on the left turned out to be a species of Ptychodus that was super common here (maybe anonymous?) while the tooth on the right was a perfect anterior Cretoxyrhina mantelli, my first of that species! Unfortunately I still don't own a rock hammer and even if I did I would have forgotten to bring it. I'm so used to just walking around at a site and surface collecting that the most I ever pack on fossil hunting trips is a garden trowel. At first I told myself I'd leave the teeth for a return trip when I had proper tools, but my impatience got the better of me as the hours wore on and I ended up using my trowel as an impromptu chisel and a rock as a hammer. The root of the Cretoxyrhina tooth broke in one place but I saved it for reattachment later. 

 

 

My troubles weren't over when I finally got the tooth out of the rock, however. My attempts to pry it out with a screwdriver on my walk back to my car were far from successful and actually caused my thumb to slip at one point, forcing the the tip of the tooth up and underneath my nail. Ninety million years since it was alive and this particular Ginsu shark finally got to taste blood again (even if it was only because of my stupidity ). 

 

 

Rewinding back a little bit to when I first found the site, I was able to follow the layer that I first spotted the Ptychodus and Cretoxyrhina in to the left where it was better exposed. It turned out that although there were obviously teeth in the grey/tan, fine-grained layers roughly three to four inches above the bentonite seam (the two teeth I just mentioned being examples), the vast majority were to be found within the red-stained "contact layer" immediately above the bentonite. A super thin lense was sandwiched between the bentonite and the dense shale/siltstone above. Here's a picture of the lense as I first saw it: 

 

 

Over the course of the next couple of hours I had my hands full pulling out shark tooth after shark tooth. There were so many in such close proximity that just a single small four by five inch slab of the red contact lense contained three decent sized Squalicorax teeth, a small Ptychodus, a fish vertebra, and an uncountable amount of microscopic fish teeth and other vertebrate detritus. I personally love in-situ photos, so I took a couple to show off. 

First up, a nicely-preserved Ptychodus anonymous. With the stratigraphy of the site more or less ironed out now, I'm pretty sure that the majority of Ptychodus teeth I found were P. anonymous with a couple of the much less common P. decurrens mixed in for variety.

 

 

An incredibly small palatine bone from an Enchodus with the trademark fang intact, surrounded by a jumble of fragmented bone and teeth detritus. 

 

 

The blade of a Squalicorax falcatus peeking out from the contact lense. This specific tooth turned out to be the largest example of the species I've ever found (just barely bigger than those from Post Oak Creek!).

 

 

How it looked once it was cleaned up:

 

 

My blurry attempt at using an iPhone camera to take a closeup of the incredible serrations of a different Squalicorax tooth sticking out of a piece of the contact lense: 

 

 

One of the bigger fish scales I saw at the site. Every piece of shale was absolutely covered in them. 

 

 

Yet another Ptychodus tooth (probably P. anonymous). 

 

 

A second large Cretoxyrhina mantelli anterior tooth. This one still required some time spent with a dental pick but it proved to be much easier to retrieve than the first one I found. A before and after:

 

 

 

And just to show how abundant the teeth were at this site, here's a picture showing the result of only four minutes' worth of digging and picking around: 

 

 

The best find of the day turned out to not be one of the shark teeth, but a tiny little bone that I didn't find particularly interesting when I first pulled it out of the shale. Any guesses as to what it might be? (Hint: this is a view from the bottom side) 

 

 

If you guessed vertebra, you're right! And you're also a lot smarter than I me  - my lack of interest was because I thought I was looking at part of a crab carapace. 

This particular vertebra is from a Coniasaurus (an ID provided by @Jared C) - and it wouldn't be the only one I'd find here. But I'll leave that for the next post since I'm running out of space for pictures and I've already rambled for too long. 

I'll leave you all with a group picture of the finds from that first day:

 

 

- Graham 

[Fin Lover]

Looks like a great trip, other than the thumb.  That hurts just looking at it!  Great finds and nice pictures to take us along on the journey.

[Mikrogeophagus]

Man I've been seeing so much coniasaurus stuff these days... I need to hop on the eagle ford train soon. Your recent trips are great motivators . 

[JohnJ]

Tabloids are not what they used to be.  I looked all over them for the story: "Man Bitten by SHARK in Central Texas!"  Couldn't find it....  

 

Nice work and finds, Graham. 

[Jared C]

Love it! Looks like my trip reports need a revival now due to the competition from your awesome recent write-ups 

 

Looking forward to seeing the more detailed story about this Coniasaurus materiel I keep hearing about 

[Gizmo]

Very nice, congrats!