There is a large stone in the Union Dale Cemetery, Division 3, an unknown section, Brighton Rd., Pittsburgh, Allegheny county, PA. It also has some RICHTER family members on it:
Sara PFAHL CUPP, 1911 - 1979
Charles B. PFAHL, 1909-1946
Martha R. PFAHL, 1882-1972
William H. PFAHL, IV, 1908-1990
Peter RICHTER, 1853-1916
Sarah T. RICHTER, 1853-1932
The top of this stone reads "RICHTER - PFAHL"
I have no more info as this is not my line. I just happened to see it.