Partial mammalian tooth?

[Oregon1955]

I have been a long time follower of the fossil forum but this is my first post.

A good friend of mine found this at the rock pile at the Rice Museum here in the Portland Oregon area. My friend is confined to a wheelchair so this location where hounds drop off rocks collected from "who knows where" is perfect for him. Anyway my buddy knows I've collected vertebrate fossils for from all over Oregon for decades and was delighted when I said was wasn't positive about what it was. So I'm coming to all of you.

 

The specimen is approximately 4cm x 5cm x 2cm. It's heavy, definitely mineralized, looks mildly water worn, and has tooth-like structure. My best guess is that it is mid root area of a large segmented tooth. Without any crown portions present, that's as far as I'm willing to go.

What say you?

[M Harvey]

very worn Equus tooth.  

[JohnBrewer]

There are numerous members who maybe able to help. I’ll tag @Harry Pristis

[abyssunder]

Welcome to the Forum!
I see just an interesting rock.

[Misha]

I would have to agree that this looks more geological than a fossil.

Equus teeth have continuous swirled chewing surfaces that should be visible even if worn, but I do not see that here.

[Oregon1955]

I greatly appreciate all the quick responses. I understand the possibility of it being Equus sp. but I don't recall ever seeing a horse tooth with this many segments (maybe M3 lower jaw?), and we have horse fossils in Oregon from the Eocene into the Pleistocene and I have found numerous specimens form the Oligocene into the late Pleistocene. However I do recall seeing Pleistocene Equus teeth from Florida that look very similar. If this is just a piece of the root and reserve crown its the biggest horse tooth I've ever encountered.

 

Not being a geologist I'd be interested by what geologic process these very organic looking structures were formed?

 

Thanks for all the responses. I love learning from engaged people.

 

[Harry Pristis]

I don't know what this is, though I know it is not from a horse.  The form reminds me of walrus tusk, but I don't see convincing evidence.  Maybe @Boessewill recognize it.

[Boesse]

Could this be petrified wood? The fourth photo makes it look like woody tissue. I'm not necessarily convinced this is tooth/tusk. Does not look like walrus ivory.

[ynot]

I am in the non fossil camp on this one.

Looks like a mineralized vien to Me.

[Fossildude19]

Looks shell like, to me. 

Maybe a rudist?  

[DeepTimeIsotopes]

It looks like a worn calcite or quartz vein. Maybe try to scratch a knife blade with it. If it does it’s quartz, if it doesn’t it’s calcite.

[Oregon1955]

Tis a puzzlement. wish i knew where it came from. it's not prototypical of any Oregon fossils I'm familiar with. its very dense and hard like many petrified woods but no detectable cellular structure. very chert like. the fossilization is complete. its not bone, maybe its plant material, maybe shell, maybe horn, maybe tooth, maybe tusk, maybe some mineral in a filled vein. heck i'm holding it and i don't know.

but it has structure. 6 tightly stacked plates. ovoid cross section. 3 of the plates are complete go all the way through the cross section and have the same exterior layer of enamel/dentin, rind, shell, bark or whatever, on both sides. I'll see an invertebrate paleontologist over xmas and report his opinion.

[Bronzviking]

I saved some of your pics to my computer and zoomed in on them. I see some woody texture in this one below. Can you zoom in on these spots and we can further examine it.

[Oregon1955]

Sure bronzviking, I will take more pix of that area later today and post them.

[Oregon1955]

Bronzviking,

Here is a close up of the area where you are seeing woodiness. This is looking from above and the area you've identified is on the left side.

Glad to post more photos if this doesn't help.

Oregon1955

[Oregon1955]

UtahFossilHunter,

Are you asking me to try scratching the stone with a knife blade or scratching the knife blade with the stone?

If it's the later...the stone scratches the knife blade.

The stone is impervious to my dental picks unless I'm applying a good deal of pressure.

Oregon1955

 

[ynot]

Either way will work.

Since it scratched the knife it is safe to say the knife will not scratch it.

This means it is most likely a quartzite mineral.

I still think it is a mineral vien piece, but the apparent layering could be from a quartzite (metamorphic sandstone.)

I do not see anything that indicates a biologic origen.

[Max-fossils]

17 hours ago, Fossildude19 said:

Looks shell like, to me. 

Maybe a rudist?  

I'm not really seeing any shell structure here... I don't know how to explain why (sorry ), but when I look at it I just can't see how this could be shell. 

Nor am I seeing bone. 

Wood is a possibility in my eyes, but I find non-biological rock to be the most likely ID. 

Count me in the mineral camp  

[Oregon1955]

I understand how difficult it is to look at pictures of a partial specimen and see the structural details. Here's a pic where I try to highlight the  structure of the plates that make up this specimen, geological or biological.

I've seen so many fossils in my over 50 years of hunting the fact I can't identify it for sure as a fossil leads me to say mineral is most likely as well...but

Anyway this pic shows in blue lines how the plates cross the middle of the cross section, the green dash line is my assumption on those portions worn away. If you zoom into pic 3 above you can see the actual lines. I don't know what it is but I'm having a hard time seeing how a crystal grew into a void and ended up looking like this but I've been wrong before.

[Bronzviking]

I'm sorry @Oregon1955 but without having this piece in hand it's so hard to ID. I was leaning towards wood but with no sign of growth rings I think we can rule out tusk and tree. Those linear lines that are running through the center could be layering of sediment and geologic. Interesting find though.

[Archie]

I agree with mineralized vein.

[ynot]

3 hours ago, Oregon1955 said:

I'm having a hard time seeing how a crystal grew into a void

Not crystal, but crystalline. That is the part that I think shows possible sedimentary layering.

[Oregon1955]

Excellent. I follow the reasoning and concur. 

I'll show it to my Dr. Buddy and report back. 

[Echinoid]

I agree with wood. 

It looks a lot like the petrified wood that comes out of the dinosaur sites at Inverloch in Victoria:

I've seen specimens with more similarities, but I don't have pictures

[Scylla]

My eyes see pet wood, but ivory possible. So since I'm usually wrong it must be something else!