Hi Lynne: Long time!! The John that was the s/o Samuel and Sarah Beall was b. abt. 1694, Montgomery Co., MD, d. 8/29/1750, MD and he married Susannah Smith on 12/1/1715. Susannah was the d/o Nathan Smith and Elizabeth Coale. I've pretty much gathered all of the Magruders I can but I don't think this John is yours. John and Susannah's children were: Nathaniel, b. abt. 1716, married Margaret Magruder; Nathan Dunblane Magruder, b. abt. 1718 married Rebecca Beall; Elizabeth Magruder, b. abt. 1720 married Richard Burgess; Cassandra Magruder, b. abt. 1722 married Henry Hilleary; Rebecca Magruder, b. abt. 1725 married Benjamin Hall; Zadok Magruder, b. abt. 1729 married Rachel Pottinger; Alexander Magruder, b. abt. 1731 married to unknown; and Burgess Magruder.
If there's anything else I can help you with please let me know.