What in the world are these?

[Earth]

I find these pretty much every time I go exploring the beaches in Delaware. Any idea? Don't want to keep picking them up if their just "whatever".....They are all made of the same substance...

 

[Eu_citzen]

Sandstone? Check under magnification and see if you can see "grains of sand" in there. Will a knife scratch it?
Fine grained rocks are hard to ID from pics alone.

 

[Earth]

I find these pretty much every time I go exploring the beaches in Delaware. Any idea? Don't want to keep picking them up if their just "whatever".....They are all made of the same substance...

Okay, I'll check it out...it's everywhere on the beach....

 

[FFFPatriot]

Those look like they could be shrunken alien heads?