Fossil ivory

[Ninjafossils]

I recently acquired this bone in a trade (thanks again Gatorboy!). As I pulled it out, I saw growth rings! I know they are characteristic to fossil tusks. What do you think it is from? Walrus, peccary, Proboscidean?















Notice the rings

 

[Harry Pristis]

It appears to be a chunk of dugong rib -- a very common Florida fossil.

 

[Ninjafossils]

I thought so too. But the ribs I find never have these rings.

 

[Harry Pristis]

I thought so too. But the ribs I find never have these rings.

Yeah, I know what you mean . . . mostly, the material is undifferentiated; but, occasionally, a bit will show up with these subtle rings. I don't know the reason for it.

 

[GatorBoy]

Sorry I didn't label everything better.
Harry got it right.
That one came from a phosphate mine... your welcome and thank you.

 

[Ninjafossils]

Ok. Just checking because that is the strangest piece of rib internal structure I've ever found.

 

[GatorBoy]

Here is another one.
Someone intelligent once brought up the idea that the lack of marrow cavity in a portion of Dugong rib along with its density could have acted as ballast.
Pretty good thought.