Bone from New Jersey beach

[Parthicus]

I found this (probably modern) bone on a New Jersey beach a few years ago, and it has been puzzling me ever since.  The large flat area, and the edges that look like they interlock closely with other bones, makes me think this is a skull element, presumably from a marine mammal.  But it doesn't seem to closely match any of the dolphin or whale skull bones that I can make out in photos I found online.  Any help is appreciated.

[jcbshark]

Looks like a piece of turtle plastron to me

[Neanderthal Shaman]

I think ^ is right. Look up "turtle shell fragments" and you'll get lots of similar looking pictures.

[ClearLake]

Correct, a piece of turtle shell.  you can see the edges where the various segments fit together as you mentioned.  You can also see the lines indicating where the edges of the chitinous scutes were (but are gone now).  With the proper comparative material,  I'm sure it could be identified to a specific type of turtle.

[Parthicus]

Thanks for the replies everyone, it does seem to be a piece of turtle.  I grew up in New Jersey and have continued to visit the shore there most summers, and never knew that sea turtles can be found so far north.  It looks like there are at least three species regularly spotted off New Jersey waters.  Definitely my coolest (non-fossil) beach find!