Thanks.You have some great information here.I have forwarded it on to Robert Allen and have told him that I will give you he email address.He can definitely talk more intelligently to you than I can.
The records of Greene County, Illinois are full of information on Thomas and Zachariah.So far as I know those writings are the source that they were brothers.However, I do recognize that not all early writings were correct and it is possible that some author made that assumption, put it in print, and now that is what everyone goes by!!!So - maybe they were cousins.........(?)His tombstone in Greene Co. gives age of of 66 and he died 7 Sept 1832.Zachariah's tombstone indicates age of 78y 7mo 16 d with a death date of 24 July 1838.
Could you contact me direct - firstname.lastname@example.org - so I can give you Robert's email address?Thanks!