Please see the Maryland Genealogical Society Bulletin, WinTer 1996, Volume 37, Number 1, page 67, article:The Maccubbin Family of Montgomery County by William M. LeoGrande and Jerome F. Collins. Page 70 gives an excellent narrative on Zachariah MacCubbin and Mary Marshall. Mssrs. LeoGrande and Collins have excellent documented references for their data and conclusions. I personally have not verified their information since this is not a direct line of my family. But have found that their referenes to my direct family lines have been accurate. Good luck.