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Sharktooth Hill Trip Report

Part 1 – building the sifting table

 

Hi everyone,

 

After my first trip to Sharktooth Hill in June, I was hooked. I immediately started making plans to return and, this time I’d come better prepared. This forum has provided an amazing source of ideas and helpful people and inspired me to build a sifting table for my next trip to STH. A huge thanks to those who have helped me by answering questions, providing pictures and ideas, and helping me troubleshoot. I gathered as much info as I could and then tried to combine all the best ideas into one contraption to fit my needs. I’m excited to try this beast out next week!

 

It’s big! The screen is 37.5” x 21” and the table stands about 4 feet tall but I will lower it if the height proves too high to load easily. I don’t want to sacrifice “wobbly-ness” though, because I’m hoping that’s going to do a lot of the sifting work for me. Plus, my son and I are 6’5” and 6’4” so a tall table should be ok. I used SCH 40 PVC and the 2 rectangular bases are glued while the 4 legs are removable to allow for compact storage/transport. In limited testing everything stayed together but I’ll bring some PVC glue with me in case I need to solidify it in the field. I'll also bring my PVC cutter for “disassembly” for the way home if need be.

5d74103e8a801_siftingtable.thumb.jpg.723ca2ef88582c7bd77f34edbc8c9e05.jpg

 

The bottom tier is ¼” mesh and has 6 “T” brackets to make sure it stays on top of the PVC frame. I bolted on a handle to allow it to be shaken one- or two-handed. There are no pointy parts on the inside (trying to avoid bleeding as much as I did on my last visit to STH).

 

5d7410c2f30cb_bottomtier.thumb.jpg.54982de973403656a73a3fef1da9755f.jpg

 

The top tier is ½” mesh and sits inside the bottom tier. Corner braces in the bottom tier (see above) allow the upper tier to sit low enough that it won’t dislodge but high enough that the contents can move freely across the bottom mesh. Initially I was disappointed that the large size and my inability to “tighten” that mesh caused it to sag noticeably once it was loaded up with soil. I remedied this with the addition of an adjustable bracket along the midpoint. But then when I put the top tier inside the bottom tier I realized I’d created a teeter-totter (doh!) and had to chisel out a groove on each side to allow it to fit in there.

 

5d7411ce39e74_toptier.thumb.jpg.55f33a223ebd73c081be1042ebd59e0a.jpg

 

I’m very excited to go give it a try and I hope you all find this pre-trip report interesting. I’m happy to answer any questions and/or accept suggestions for improvement. And thanks again to all the helpful people on this forum whose previous pictures, design notes, and conversations encouraged me to attempt this (and make this post). I’ll send a follow up trip report after I get home.

Cheers!

 

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Wow, that is really nice.  STH has lots of nice shark, ray and bony fish micro teeth.  There are a number of good posts on them here on TFF.  However, because of their small size they will all fall through 1/4" mesh.

 

Marco Sr.

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8 minutes ago, MarcoSr said:

However, because of their small size they will all fall through 1/4" mesh.

Yes! And I've got a set of sieves (fit over 5 gallon bucket) with mesh of 1/8", 1/20" and smaller that I'll use to go through my tailings pile and bring home for careful picking. I don't want to cut too deep into my time to find big teeth with my sieving for the smaller ones, so I was thinking (your input appreciated here) that perhaps I'd use the table to sift for bigger stuff then when I encounter a relatively heavy density of teeth, I'd take a little time out to sift the top of my tailings pile through the 1/8" or 1/20" sieve to bag and take home.   

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One thing to point out. You will probably  want to make some small sand bags or the like to put on those base rails as this is going to be incredibly top heavy and always want to tip. The weight on the bottom will help to steady the frame.

Just take some empty cloth bags with you, fill them up with overburden matrix have some office clips or zipties to close and merely empty them for transport home.

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1 minute ago, caldigger said:

Just take some empty cloth bags with you, fill them up with overburden matrix have some office clips or zipties to close and merely empty them for transport home.

awesome idea - thanks!

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4 minutes ago, ScottM said:

Yes! And I've got a set of sieves (fit over 5 gallon bucket) with mesh of 1/8", 1/20" and smaller that I'll use to go through my tailings pile and bring home for careful picking. I don't want to cut too deep into my time to find big teeth with my sieving for the smaller ones, so I was thinking (your input appreciated here) that perhaps I'd use the table to sift for bigger stuff then when I encounter a relatively heavy density of teeth, I'd take a little time out to sift the top of my tailings pile through the 1/8" or 1/20" sieve to bag and take home.   

Yes, thats the way to do it!  When you dump your screens make sure you toss the larger clumps off to the side so you don't have to contend with them when sifting the small stuff that fell through your larger screens.

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2 hours ago, ScottM said:

Yes! And I've got a set of sieves (fit over 5 gallon bucket) with mesh of 1/8", 1/20" and smaller that I'll use to go through my tailings pile and bring home for careful picking. I don't want to cut too deep into my time to find big teeth with my sieving for the smaller ones, so I was thinking (your input appreciated here) that perhaps I'd use the table to sift for bigger stuff then when I encounter a relatively heavy density of teeth, I'd take a little time out to sift the top of my tailings pile through the 1/8" or 1/20" sieve to bag and take home.   

 

1/8" (3.17 mm) sieve will catch a lot of the micro teeth but the smaller species will fall through.  1/20" (1.27 mm) will catch most of the micro teeth but a few small species like Raja, Rhinobatos, Mustelus, smaller ray dermal denticles, some bony fish teeth etc. will still fall through.  .5 mm (1/50") is the smallest sieve mesh that I  use for STH matrix.  Sieving what fell through your 1/4" screen only will take time with the small mesh screens.  You can just fill up 5 gallon buckets with what falls through your 1/4" sift and sieve at home with a number of different mesh size sieves saving the time at the site.  However, you will take home a lot of sand.  I get on a plane when I leave Bakersfield so I need to sieve my matrix at the site to get the weight/volume down so I can ship it home to Virginia in USPS large flat rate boxes before I go home.

 

Sometimes teeth sort by size/weight in a formation so the smaller teeth are not necessarily the most dense where the bigger teeth are.  Smaller teeth can get wicked away from the larger specimens in a formation by water action.  However, pockets of lots of bigger teeth tell you that you are in a good bone bed layer.

 

Marco Sr.

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Liking the high-tech shaker table--hope it works as good as it looks.

 

Looking forward to seeing pictures of it in use in the field (STH) and hearing your comments after its initial outing.

 

 

Cheers.

 

-Ken

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Looks good.:thumbsu:

 

Good luck at STH.

Looking forward to Your report.

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  • 2 weeks later...

Sharktooth Hill Trip Report

Part 2 – the sifting table in action!

 

Hi everyone,

 

Our trip to STH was great. I'm still trying to catch up with work and real-life chores, so I haven't had a chance to get the finds photo-ready, so that will have to be part 3 of my trip report for another day.

 

Bakersfield was HOT (as expected)! But with my son heading back to college soon, we were just happy to be able to get out there before he left. Fortunately we brought a pop-up and a ton of water and gatorade. Here's a view of the site.

site.jpg.3905470144845e954a3a446139993a7a.jpg

 

We did a little prospecting to try to find a promising place to set up camp, and ended up literally in the same hole I'd worked in back in June. 

hole.jpg.d3c45d38c5ac165af8c58edd5b331645.jpg

 The perfect tool for the job - 19 year-old muscle. :-) The matrix was very dry and as you can see it came out as fine silt and dirt clods that if you squeeze them hard enough you can crumble them in your hand. Our strategy was to use the abundant whale bone fragments to let us know we were in the bone bed, then break out enough matrix to fill the sifter (about 5 gallons) then load in in with a shovel.

 

Loaded and ready to go.

loaded.jpg.e004361967559248a9eea0d421554dcf.jpg

 

This beast of a sifter really made it rain once you start shaking it. 

rain1.thumb.jpg.9a61836edada9ea9d62bef9344b0fcd1.jpg

Making it rain again - here's another shot from a distance.

rain2.jpg.b37776b9cc30c9ad35777fd998be9f44.jpg

 

After the initial shaking, most of matrix was gone and we'd do a quick pick through the upper layer looking for large teeth and bones. Why agitate them any more than necessary? Then we'd break up some dirt clods and shake a little more before doing a careful search through the top level (1/2-inch mesh).

top.jpg.63ddfac61ba5cb00d362b91a81636dae.jpg

 

This process was usually quick because almost all the good stuff falls through...but if you DO find anything in the top level it's going to be something awesome! Then we'd toss that aside and examine the 2nd level (1/4-inch mesh). 

bottom.jpg.2504bbe119c7fc6b11d4f369d4dbd3ec.jpg

 

Now we had to be more careful because although the medium-size teeth are fairly easy to spot (see any above?), it also catches a lot of small ones that can hide pretty well. Here's a zoom-in on the picture above.

bottom-zoom.jpg.b9227bbfad030103b61104466c15fa69.jpg

 

Woo hoo!  When we found a decent number of teeth we'd go through the tailings under the sifting table with a 1/20-inch sieve and load whatever it caught into ziplocks. This reduced the volume immensely (at least 10:1) and as we were dumping it into bags we could easily see teeth in there. And, for good measure, we also took some additional micro matrix samples at random intervals as well. I look forward to sorting through this over the winter. I'll also be donating some to the local high school so the biology teacher can have a jar on his desk with some tweezers and a magnifying glass for students who finish their work early. Finally, just to be complete, we brought home a 5-gallon bucket of completely unsifted matrix from our hole. I'm expecting the "Honey, why is there a bucket of dirt in our garage?" any day now.      

 

The sifting table worked like a dream and looks just as good after 2 days of nonstop use as it did before we began. Couldn't be any happier with it. Thanks to those of you here in the forum who posted pics and patiently answered my questions! We were able to move a LOT of matrix in our search for teeth. The only unexpected thing that happened was that while I assumed the silt tailings would bury the legs over time, that did not happen. The rocking motion was enough to keep the sifter riding high on top of the tailings pile. Because physics, I guess.  

 

I'll do another update once I get the teeth cleaned up. Or maybe just the big ones at first. 

 

And if anyone has any questions about the site, the sifter, or anything else, I'd be happy to answer. I should also mention that Rob was a great host at the quarry and I'll definitely be heading back.

 

Thanks for reading!

Scott

 

 

 

 

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:thumbsu:

 

Congrats on what looks to be a very successful mission!

 

 

Cheers.

 

-Ken

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  • 1 year later...
PrehistoricWonders

Hey!

I realize this topic is old, but did you ever happen to get any pics of the haul? 

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ScottM
On 5/4/2021 at 11:16 PM, Familyroadtrip said:

Hey!

I realize this topic is old, but did you ever happen to get any pics of the haul? 

Hey there!

Yeah - we got lots of the usual stuff, including a bucket of bones I've yet to finish going through. Probably a dozen species of sharks and rays (+more when you include the micros).

Here are some of the better teeth.

1627522338_2615(2).thumb.jpg.f4e6b632de5cd58e01ee925cc7f80e31.jpg

I also got a few matrix pieces that were a little tricky because we were working in a section of softer matrix (but better for digging/sifting!)

2906.thumb.jpg.98bb42bdfdf5178139dda97ab69c0c29.jpg

2908.jpg.f490505c0ce92d67c45a7b64686feb23.jpg

And here are a couple of my favorites from the next trip, but same place, same sifter.

IMG-8379.thumb.jpg.263981edebd13f8be1b4070c951001c6.jpg

2887.thumb.jpg.da00a1d46a8fd6415a6d38a0f4463711.jpg

Scott 

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historianmichael

That Hexanchus is really cool. Great find!

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PrehistoricWonders

You killed it! Love the hastalis, planus, and especially that cow!

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  • 1 month later...
HemiHunter

Your sifter setup is truly awesome!  As an engineer nerd, I appreciate the design!

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