Artifact or geological phenomena? ?

[suskypaddler]

I found this a while ago on a friends property in south eastern Pennsylvania.
I dismissed it at first as just a cool rock but I am now interested if anyone has any opinions otherwise.

 

[suskypaddler]

How do I attach pictures?

 

[Rick (Nova Scotia)]

Edit your original post, scroll down past where you type, look for "attach images" or if you have them stored on another site like photobucket etc, you can click one of the icons above where you type, it's the 4th from the right.