Lee Creek Micros That Would Fall Through Window Screen

[MarcoSr]

I want to thank Don for sending me a small USPS package of matrix containing Lee Creek mine reject material from North Carolina. The matrix was well washed, clean and very easy to look through. It also was very shelly. I’ve found that the very shelly reject material has specimens that are in great condition and can contain some of the rarer species like cookie cutters. Don sifted this material with a .75mm strainer which captured smaller specimens which would typically fall through standard window screen but did remove most of the fine quartz and other fine debris.

I normally screened my reject material with window screen in the past and was curious what might be in the smaller material which could fall through the window screen. I found the larger specimens that you typically find when you screen with window screen. I’m not posting them because I’ve posted similar specimens before. What I want to show in this post is some of the specimens that would typically fall through window screen. These specimens were in the .75mm to 1mm size range. I’ve looked through Lee Creek reject material for years and until now hadn’t found a Mustelus sp. I also found smaller specimens of Dasyatis, Raja and Mobula plus a dermal element. I’m still curious as to what other species can be found in this finer material.

If you place your cursor on a JPEG image you will see the file name which will have the specimen id as best that I can determine and the specimen size. Each matrix that I search makes me more of an avid micro tooth collector. If anyone has or can collect good matrix with shark, ray, and fish micros please send me a PM.

Purdy et (al 2001:140) included as Mustelus sp. teeth from the Pungo River Formation (Units 1-5, Early-Middle Miocene of NC). Specimens have also been found in basal Yorktown 2 sands. Below are pictures of the specimen that I found:

Other specimens:

Dasyatis:

Raja:

Mobula:

Dermal element:

So I think it is definitely worthwhile to take finer material from the Lee Creek reject material every now and then, just to see what might be in it. However, I don’t think going below .5mm would yield shark or ray specimens.

Marco Sr.

[jcbshark]

Very nice pics as usual Marco.I've thought about trying a smaller sieve in my creek but as of yet haven't gotten around to it.

[MarcoSr]

Very nice pics as usual Marco.I've thought about trying a smaller sieve in my creek but as of yet haven't gotten around to it.

Jeff

Upper Cookie Cutter teeth are not known from the fossil record or are extremely rare. There are a lot of postulated reasons why they are not found like they are so small or that the cookie cutters swallow them instead of shedding them from the mouth or that they don't fossilize like the lowers. With the high density of lowers in your creek you could find one using a smaller sieve. You could also find other neat really small species. The real drawback is that it can be quite time consuming and sometimes tedious to look at the smaller matrix especially if you aren't finding a lot. But I would think it would be worth looking at a sample.

Marco Sr.

[jcbshark]

Thanks Marco,I'm sure it would be a fair bit of work more than what I currently do but maybe I could try a small batch to see what I come up with.I'm always up for finding anything I don't already have : )

[Sacha]

Marco, I haven't invested in a proper set of screens, but am still using a pair of 18" x 24" screens at 1/4" and then window screen for the material I send you and John. I can collect allot of material in an hour or so that way. Since Jeff and I are apparently, and very willingly, becoming raw material suppliers to you guys, I think you should direct us in our collecting efforts to better serve you. Should we buy a set of those round gold screens and when we do, then what shall we use to get you your material.

We can continue getting mass quantities with our current tools, we can switch to specific certified screen dimensions or we could do both in different quantities.

I'm happy to do anything as you suggest. Looks like you've got Jeff hooked as well, so we might as well get the proper tools and use them correctly.

[jcbshark]

Hey Sacha,have you looked thru any of the micro stuff yet?Btw I'm planning on a trip out to Arcadia after the holidays and I'm hoping a few forum members that I've been speaking with will go.I know your not a weekend hunter but if you are interested I'll let you know when I narrow down a date.I plan on going to a creek out there I've hunted in the past a few times.No secret spots but there's plenty to find.

[MarcoSr]

Marco, I haven't invested in a proper set of screens, but am still using a pair of 18" x 24" screens at 1/4" and then window screen for the material I send you and John. I can collect allot of material in an hour or so that way. Since Jeff and I are apparently, and very willingly, becoming raw material suppliers to you guys, I think you should direct us in our collecting efforts to better serve you. Should we buy a set of those round gold screens and when we do, then what shall we use to get you your material.

We can continue getting mass quantities with our current tools, we can switch to specific certified screen dimensions or we could do both in different quantities.

I'm happy to do anything as you suggest. Looks like you've got Jeff hooked as well, so we might as well get the proper tools and use them correctly.

John

I've been looking through matrix for probably 20 years now and haven't invested in a good set of screens. I use typically fine flower sifts or fine kitchen strainers (usually .5mm to 1mm) which I buy very cheaply when I'm not using window screen. Clay formations really clog up the very fine screens so I usually don't go below 1mm with clay. A lot of the formations don't have much that falls through window screen. You need to test a sample to see if the finer material contains specimens that makes the extra effort in collecting and searching finer matrix worthwhile. I used to collect matrix that was incredible at a now closed Eocene site in Virginia. However window screen pretty much captured everything and going to finer screens wasn't worth the effort and didn't yield different species. Although matrix from sites like Shark Tooth Hill and a lot of the Cretaceous sites does have a good number of specimens down to .5mm. Don got the matrix for this post using a fine kitchen strainer which was .75mm which he bought for $3. So I would recommend that you just keep an eye out for a cheap flower sift or fine kitchen strainer and at some point take a small sample of fine gravel from your sites. If the fine gravel has different species that make the effort worthwhile then you can take larger quantities. I really do appreciate your efforts and Jeff's and the matrix that you both have sent to me.

Marco Sr.

[Sacha]

Hey Sacha,have you looked thru any of the micro stuff yet?Btw I'm planning on a trip out to Arcadia after the holidays and I'm hoping a few forum members that I've been speaking with will go.I know your not a weekend hunter but if you are interested I'll let you know when I narrow down a date.I plan on going to a creek out there I've hunted in the past a few times.No secret spots but there's plenty to find.

Jeff I'd be up for that. We're home until just after Christmas and returning on the 4th of January. I'll make any time after work for me.

[jcbshark]

Sounds good,I'll let you know when I have it narrowed down to a weekend.

Edited December 12, 2013 by jcbshark

[AeroMike]

Marco, if those could pass through a screen door (bad joke visual right now lol) then your macro pic taking abilities are outstanding~!. About 4 years ago I went ot Aurora and and filled up eight, 5 gal. buckets of material from the piles outside the museum and screen it all but now I am thinking I still missed a ton of fossils.

[MarcoSr]

Marco, if those could pass through a screen door (bad joke visual right now lol) then your macro pic taking abilities are outstanding~!. About 4 years ago I went ot Aurora and and filled up eight, 5 gal. buckets of material from the piles outside the museum and screen it all but now I am thinking I still missed a ton of fossils.

The specimens in this post are all 1mm at the largest dimension or smaller. Typically window screen openings are around 1.5mm at the smallest dimension. Sometimes smaller specimens do get captured by the window screen because they stick to something else or don't get right to the screen when sifting. However if you do a real good job sifting and/or washing the matrix most fall through. The shelly matrix from Aurora does have a good number of these small specimens. The Aurora matrix that is mostly pebbles didn't seem to have much in the fine matrix. The first time I washed and sifted Shark Tooth Hill matrix I used window screen. I washed the matrix on the window screen over a sift over my wheel barrow and used what fell through to fill a couple of small holes in my field. When I was trying to identify what I found in the matrix I realized how small specimens from Shark Tooth Hill could be. So I dug some of the matrix out of the holes in my field and sieved it with a .5mm sieve. I found several hundred specimens after doing this. Almost as many as I found in the window screened material. So from some sites it is definitely worth using a finer sift than window screen.

Marco Sr.

[sixgill pete]

3 Mustelus, nice Marco. As good as this particular matrix does look, I have yet to find a Cookie Cutter in it.

[MarcoSr]

3 Mustelus, nice Marco. As good as this particular matrix does look, I have yet to find a Cookie Cutter in it.

Don

Unfortunately only one Mustelus, 3 different views. But this was my first specimen from Lee Creek matrix. Mustelus are very common in the Virginia Formations of the same time period so I imagine if you look at a good amount of finer shelly matrix from Leek Creek you will find a good number of them. I did find two cookie cutters in just under 3 gallons of washed shelly matrix that I brought home from the Aurora Fossil Festival two years ago. I think this is the matrix type from Lee Creek that you do have a decent chance of finding a cookie cutter in good condition. Thank you again for the matrix.

Marco Sr.

[cowsharks]

Jeff

Upper Cookie Cutter teeth are not known from the fossil record or are extremely rare. There are a lot of postulated reasons why they are not found like they are so small or that the cookie cutters swallow them instead of shedding them from the mouth or that they don't fossilize like the lowers. With the high density of lowers in your creek you could find one using a smaller sieve. You could also find other neat really small species. The real drawback is that it can be quite time consuming and sometimes tedious to look at the smaller matrix especially if you aren't finding a lot. But I would think it would be worth looking at a sample.

Marco Sr.

Marco, many years ago when I was collecting at Muddy Creek I asked the same question as to why we didn't find upper Cookie cutter shark teeth. As rich as that material was with mico material, no one (even Mike F.) seemed to find an upper Cookie cutter (Bill H. thinks he found one I believe). I spoke to Dr. Hubbell about this and he mentioned the same reasons that you referred to. I spent quite some time searching for any documented cases of someone finding a fossil specimen of an upper Cookie cutter but never found any. Dr. Hubbell even pulled out one of his extant Cookie cutter jaws and described the size/shape of the tiny uppers. Eventhough they are tiny, I would still think they should fossilize just like the paper thin lowers, but who knows, it remains a mystery I guess.

Daryl.

[MarcoSr]

Marco, many years ago when I was collecting at Muddy Creek I asked the same question as to why we didn't find upper Cookie cutter shark teeth. As rich as that material was with mico material, no one (even Mike F.) seemed to find an upper Cookie cutter (Bill H. thinks he found one I believe). I spoke to Dr. Hubbell about this and he mentioned the same reasons that you referred to. I spent quite some time searching for any documented cases of someone finding a fossil specimen of an upper Cookie cutter but never found any. Dr. Hubbell even pulled out one of his extant Cookie cutter jaws and described the size/shape of the tiny uppers. Eventhough they are tiny, I would still think they should fossilize just like the paper thin lowers, but who knows, it remains a mystery I guess.

Daryl.

Daryl

I'm not aware of a fossil cookie cutter upper tooth either but there may be a few out there like Bill H's tooth. I'm hopeful that Jeff might find one from his Creek if he starts looking at finer matrix because of the high density of lowers in the matrix.

Marco Sr.

[caldigger]

Just to throw this into the mix...if the shark swallowed the upper teeth, wouldn't it stand to reason that it would poop said teeth out the other end , thus depositing them in the same general area? Do these teeth get digested?

[MarcoSr]

Just to throw this into the mix...if the shark swallowed the upper teeth, wouldn't it stand to reason that it would poop said teeth out the other end , thus depositing them in the same general area? Do these teeth get digested?

These upper cookie cutter teeth are pretty small so they may not get through the digestive process, stomach acid and digestive enzymes, intact. Larger shark teeth do sometimes get through the digestive process or get regurgitated and have a very distinctive look and patina like appearance.

Marco Sr.

[siteseer]

Somniosus uppers are also incredibly rare where lowers are just very rare. I think part of it is that squaliform roots are so porous that they crumble easily - perhaps not often surviving as a fossil and those that do must endure the abrasive action of screening.with the remaining crown dropping vertically even through some of the finer meshes.

I began to wonder about this during my STH collecting. You can find a good number of Squalus occidentalis teeth in a day but the roots are usually mostly gone. I think it's at Slow Curve that I got some complete roots with the preservation so good you can see several foramina.

Jess

Jeff

Upper Cookie Cutter teeth are not known from the fossil record or are extremely rare. There are a lot of postulated reasons why they are not found like they are so small or that the cookie cutters swallow them instead of shedding them from the mouth or that they don't fossilize like the lowers. With the high density of lowers in your creek you could find one using a smaller sieve. You could also find other neat really small species. The real drawback is that it can be quite time consuming and sometimes tedious to look at the smaller matrix especially if you aren't finding a lot. But I would think it would be worth looking at a sample.

Marco Sr.

[siteseer]

Marco Sr.,

I knew I had seen a shark dermal denticle similar to your "dermal element" somewhere. My car is in the shop over the weekend so I spent much of the day reading, especially Bruce Welton's article on that Late Eocene partial skeleton of a basking shark. I looked a couple of other basking shark references and saw a figure that might interest you (Hovestadt and Hovestadt-Euler, 2011: fig. 5, g-h). That Cetorhinus (now called Keasius by Welton) parvus dermal denticle is very similar to yours. Check it out if you have it..

Jess

link to abstract: http://link.springer.com/article/10.1007%2Fs12542-011-0118-9

Dermal element:

Dermal element 1mm.jpg

So I think it is definitely worthwhile to take finer material from the Lee Creek reject material every now and then, just to see what might be in it. However, I don’t think going below .5mm would yield shark or ray specimens.

Marco Sr.

[MarcoSr]

Marco Sr.,

I knew I had seen a shark dermal denticle similar to your "dermal element" somewhere. My car is in the shop over the weekend so I spent much of the day reading, especially Bruce Welton's article on that Late Eocene partial skeleton of a basking shark. I looked a couple of other basking shark references and saw a figure that might interest you (Hovestadt and Hovestadt-Euler, 2011: fig. 5, g-h). That Cetorhinus (now called Keasius by Welton) parvus dermal denticle is very similar to yours. Check it out if you have it..

Jess

link to abstract: http://link.springer.com/article/10.1007%2Fs12542-011-0118-9

Jess

Thank you. When I first saw the dermal denticle/element my first impression based on the enamel tip shape and size was Bramble. However, the base was different from the other three Bramble dermal denticles/elements that I have from Lee Creek. That would be very interesting if it was Keasius parvus. I have been in recent contact with Bruce Welton about basking shark material. He has two papers in the works on them which hopefully will be out shortly. I'll definitely send him some pictures for his opinion and try to obtain the article which you referenced.

Marco Sr.

Edited December 15, 2013 by MarcoSr

[MarcoSr]

Somniosus uppers are also incredibly rare where lowers are just very rare. I think part of it is that squaliform roots are so porous that they crumble easily - perhaps not often surviving as a fossil and those that do must endure the abrasive action of screening.with the remaining crown dropping vertically even through some of the finer meshes.

I began to wonder about this during my STH collecting. You can find a good number of Squalus occidentalis teeth in a day but the roots are usually mostly gone. I think it's at Slow Curve that I got some complete roots with the preservation so good you can see several foramina.

Jess

Jeff

Upper Cookie Cutter teeth are not known from the fossil record or are extremely rare. There are a lot of postulated reasons why they are not found like they are so small or that the cookie cutters swallow them instead of shedding them from the mouth or that they don't fossilize like the lowers. With the high density of lowers in your creek you could find one using a smaller sieve. You could also find other neat really small species. The real drawback is that it can be quite time consuming and sometimes tedious to look at the smaller matrix especially if you aren't finding a lot. But I would think it would be worth looking at a sample.

Marco Sr.

Jess

If Jeff is able to find one or two uppers from his Creek that might solve some of the mystery especially if they look like or don't look like they passed through the digestive system or had roots/didn't have roots etc. I think if you are going to find an upper because of the density of cookie cutter lowers in Jeff's Creek that would be the site where you would have a chance.

Marco Sr.

[Al Dente]

Unfortunately only one Mustelus, 3 different views. But this was my first specimen from Lee Creek matrix. Mustelus are very common in the Virginia Formations of the same time period so I imagine if you look at a good amount of finer shelly matrix from Leek Creek you will find a good number of them.

Marco Sr.

I used to find quite a few Mustelus in the Pungo that I collected from the mine. I have also found a location on the Tar River where the Yorktown produces quite a few Mustelus. Here's a slide of small teeth and denticles that I collected on a 0.6 mm screen from the Pungo River Formation. It shows a few Mustelus with skate and ray teeth including Gymnura teeth.

[MarcoSr]

I used to find quite a few Mustelus in the Pungo that I collected from the mine. I have also found a location on the Tar River where the Yorktown produces quite a few Mustelus. Here's a slide of small teeth and denticles that I collected on a 0.6 mm screen from the Pungo River Formation. It shows a few Mustelus with skate and ray teeth including Gymnura teeth.

mix.jpg

Nice specimens. I can see at least 4 real nice conditioned Mustelus on your slide. I wonder if they are as common in the reject material from the mine as they were in the Pungo matrix taken directly from the mine itself? I haven't found any Gymnura yet from Lee Creek but they are also really small and will definitely fall through window screen. Is that a Gymnura at the bottom/middle of your slide or a Mobula? I can't quite see the crown well enough to tell. The only site that I have found a good number of Gymnura from is Shark Tooth Hill, CA. But I always sieved that matrix using a .5mm sieve versus window screen for sites like Lee Creek. There definitely are some different species that you can find in the Lee Creek matrix if you try sieving it with a .5mm sieve. I'm also still hoping to find a Pristiophorus oral tooth from Lee Creek like John H. has.

Marco Sr.

[siteseer]

Marco Sr.,

Can you distinguish whether the reject is Pungo River matrix? The denticle seems to be cetorhinid in any case

Jess

Jess

Thank you. When I first saw the dermal denticle/element my first impression based on the enamel tip shape and size was Bramble. However, the base was different from the other three Bramble dermal denticles/elements that I have from Lee Creek. That would be very interesting if it was Keasius parvus. I have been in recent contact with Bruce Welton about basking shark material. He has two papers in the works on them which hopefully will be out shortly. I'll definitely send him some pictures for his opinion and try to obtain the article which you referenced.

Marco Sr.

[Al Dente]

Marco Sr.,

Can you distinguish whether the reject is Pungo River matrix? The denticle seems to be cetorhinid in any case

Jess

The reject material is primarily from the main ore body which is the lower part of the Pungo River Formation but a lot of the overburden falls in on the dragline shovels as they scoop up the ore so all material that occurs in the mine can be found in the reject.