I posted some info on the B&W Forum...
These alien stones/rocks have been a visual phenom for at least 15 years. I spotted about 10-15 of them while still working in 2009 on the dirt roads around Camp David.
No one knows who or were they came from yet they still exist! No adhesive or glue keep the rocks intact.
Local lore in the area attribute that to the Catoctin Sasquash aka "Uncle Joe" whose "sleepwalking" needed markers to get him back to the Camp David compound!
