I'm working on this line for a friend, who is descended from David & Margritt's son Morgan. David & Margritt's other children included David, & Joseph, as you mentioned in your earlier note. You mentioned a son John; I have a Jean b abt 1688, no further information, who might be John. They also had Waugh, b abt 1684, & Elizabeth, b abt 1686.
So I think you are likely right that Dr. David's father was your John Darnall who was b in the 1630s & emigrated from England.
Would you mind sharing your sources for John Darnall, the immigrant? And for Margritt's surname of Morgan? I have also seen her called Margritt Mott, but I haven't seen any sources mentioned. Maybe she was married twice & one of those names was her other married name. Or something.
I have seen another message posted that said that Dr. David & family lived in St Marys Co., Maryland, until the late 1600s, when they were encouraged to leave because of their religious & political beliefs.
Thank you so much!