Hello, My name is Lee Howard, I know I am a little late on the thread. But if you are still interested in history on the Blackwell's, I am cousins with Marshall Blackwell's great grand children, and I hunt on the family land on Society hill rd. My cousins are kin to the blackwell's through their grandmother who is Marshall Blackwell's daughter. Hunting there my whole life I have learned many stories about blackwell's and interesting events that have taken place in Rockville, most of which revolve around Marshall's brother Carlos 'slats' Blackwell. There is also an old cemetery in the middle of the woods, as well as a lineage book that list anything from slaves owned, to family members.