Has anyone been to the Acheson burial plot in Washington Cemetary in PA?

Or does anyone have any photos or information about all of the Acheson's buried there?

I have the reference from A.W. Acheson's book about them attending the burial of their mother, Mary wife of David on August 4th, 1872, but that's all I have been able to find online.

If no one has found anything, I guess that means stopping there on my next genealogy trip to the east coast.

thanks,

Lois