Small fragment found at big brook. Appears to be either enamel or bone with interlocking hexagonal structure on the surface.

[TRexEliot]

Found this tiny fragment on a trip to Big Brook yesterday. I've been visiting Big Brook for a long time, and have never come across anything like it. Appears to be a small shard (about .5x1cm) of bone or enamel with a scale-like hexagonal structure on one side, and a bony texture on the other.

[Carl]

This is a piece of chondrichthyan cartilage. You may hear a lot of people reflexively say this is from a shark but it could just as easily be from a chimaeroid, a ray, or a sawfish.

Edited April 12, 2023 by Carl

[TRexEliot]

@Carl oh wow! That was at the back of my mind, but seemed too crazy to be true. Does that mean the hexagons are denticles?

[Carl]

7 minutes ago, TRexEliot said:

@Carl oh wow! That was at the back of my mind, but seemed too crazy to be true. Does that mean the hexagons are denticles?

Not denticles but individual cartilage units called tesserae.

[TRexEliot]

Just now, Carl said:

Not denticles but individual cartilage units called tesserae.

Thanks for the information! Definitely my favorite find of the trip now that I know what it is! Do you know how rare cartilage fragments like this would be? First time I've seen something like it at Big Brook

[Jeffrey P]

I would consider cartilage from the Cretaceous of New Jersey as somewhere between uncommon and rare, rarer than say a mosasaur tooth. Eleven years of collecting has only produced one of those in my collection, though I know others who have found more of them. 

Edited April 13, 2023 by Jeffrey P

[Carl]

22 hours ago, TRexEliot said:

Thanks for the information! Definitely my favorite find of the trip now that I know what it is! Do you know how rare cartilage fragments like this would be? First time I've seen something like it at Big Brook

I agree with Jeffrey: they are on the rare end of things. I have been collecting since 1988 and have maybe a couple dozen pieces from Big Brook.