It seems I found it in the same place you did. I figured you may have already tried to call the cemetery, but I thought I would suggest it just in case (I replied to several other posters who were looking for burial places, and when I suggested calling cemeteries in the area where the person died, they said they had never thought to do that!).

Maybe the town clerk of Lambertville would know who to contact regarding the cemetery's records.

Good Luck!