North Sulfur River - May 27th

[BudB]

I drove down to the North Sulfur River Friday morning. It was my first trip to the new temporary fossil park. This part of the river was my favorite even before the new park. But it looked very different in 2020 than it does now. It's a muddy mess right now. There were clean washed gravel bars everywhere in 2020, but now the gravel bars are all covered with dried mud and clay pieces. I wondered if the diggers and sifters had the better plan Friday, but I didn't bring my sifter, so I made a long hike away from the bridge, and spent my time searching gravel bars. With so many clay pieces covering everything, it was harder to spot fossils, but I still had what I thought was a great day. I'm going back and bringing my girlfriend tomorrow morning, for her first fossil hunting trip ever. She has always been fascinated by the stuff I bring home, and will finally get the chance to try it out herself. We almost certainly won't hike as far as I did Friday, and after a holiday weekend of fossil hunters picking over the gravel bars, it seems unlikely that we'll find nearly as much as I did Friday, but we'll see.

 

Some in situ photos from the day.

 

Edited May 29, 2022 by BudB

[BudB]

Here is what I brought home.

 

[BudB]

Because of the conditions, I spent more time than usual on elbows and kneepads, and got myself quite a collection of Hamulus worm tubes. I'm not sure anyone else bothers picking these up, but I've always thought they looked cool, and put them in the backpack when I find them.

 

Edited May 29, 2022 by BudB

[BudB]

This enchodus fang is the most complete one I've ever found.

 

[BudB]

Here are the other teeth from the day. I'd never found four teeth on the same day at NSR before, but like I mentioned, I did spend more time on kneepads than usual.

 

[BudB]

I couldn't resist picking up this rock. It has two embedded bacculites that perfectly show the two types of bacculites most commonly found at NSR.

 

 

Edited May 30, 2022 by BudB

[BudB]

Here are the ammonite pieces from the day.

 

[BudB]

And I was thrilled to find this mosasaur vert.

 

[BudB]

But I stumbled across the find of the day just a few steps from that vert, this piece of mosasaur jaw. It's partially embedded in rock, likely what kept it together in this large a piece. That last photo makes it look like there was a row of smaller teeth behind the big teeth. I haven't seen this in any other mosasaur jaw photos.

 

[Tidgy's Dad]

Nice finds! 

I'd pick up the Hamulus too. 

[FredFossil]

Nice finds! I’d love to find a jawbone. I was out on the river Friday too - a little to the east of you

[Jared C]

What a haul! I was going to comment on the nice S. kaupi and your baculites block, but that Mosasaur jaw is a stunner. What you're seeing in the last photo isn't a row of second teeth in a sense that a shark would have them, but rather new teeth that push up and replace the old teeth. They come in at an angle, and I remember after Mike Polcyn explained the mechanism of mosasaur tooth replacement to me (I'm blurry on it now and will  have to check again), I was surprised by the amount of movement in the jaw these teeth undergo before coming through. That being visible is a super cool pro in your specimen.

[FranzBernhard]

13 hours ago, BudB said:

I'm not sure anyone else bothers picking these up,

For sure, unfortunately, they are not plentiful in the Cretaceous over here.

Thanks for sharing also all the other good stuff !
Franz Bernhard

[pachy-pleuro-whatnot-odon]

Wow! What a haul! Over here I could spend a week searching an bring back less vertebrate material then you did in a day! Especially love the Enchodus-fang and mosasaur remains, of course, and @Jared C already said it, the "second row of teeth" are the replacement teeth starting to show through. Mosasaurs, like other reptiles, keep replacing their teeth all through their lives. When a new tooth grows, it starts absorbing the root of the old tooth it's intended to replace (you can actually see this on a rooted tooth, if ever you find one, by way of a hollow "excavated" into the root), to the point where most of the root ends up being absorbed and the old tooth being pushed out. If I'm not mistaken, in mosasaurs the teeth replacement teeth start growing in at an angle and get gradually straightened out the closer they get to replacing the tooth which place they're meant to assume. Tooth replacement is rather contentious in mosasaurs, however, as tooth replacement strategy and the way the teeth are attached to the jaw in general are arguments informative of the ancestry, the phylogenetic belonging, of mosasaurs. Really nice piece

[BudB]

Thanks for the info on the mosasaur teeth, guys. I had no idea that was what was in play here. That's so interesting.