Have you read _The Ancestry of Elizabeth Yanconish Berry_, by Dr. Brian J.
L. Berry (McKinney, TX: Prestige Printers, Inc., 1989)? Dr. Berry seems to
have consulted a great number of Cary genealogies of both the New England
and Virginia branches, as well as the Carys in England. It is his
conclusion, based partly on evidence and partly on logic, that both the New
England and Virginia branches of the Carys do indeed descend from Adam de
Kari. (It is my understanding that indisputable documentation ends at
William Cary of Bristol, b. 1492.) Dr. Berry believes very firmly that John
Cary the immigrant of Massachusetts is the son of John Cary of Bristol and
his wife Elizabeth Hereford. He says that although the Heralds' College
pedigree of 1701 states that the son John, b. 1610, went to Hackney, married
and died about 1656, there is simply no evidence that this happened, and
that John Cary the immigrant must be this son John. He further states that
although John Cary the immigrant was not a merchant like the other Bristol
Carys, his life in New England was otherwise consistent with his Bristol
origins.
I should mention that although this book concerns itself with John Cary the
immigrant, it is a useful resource for other New England and Virginia Cary
descendants who are interested in sorting out the various early Cary lines.
Dr. Berry's book is available from the Family History Library on microfiche
(#6100201, 4 fiche) and at 200 genealogical libraries around the country
(no, I don't know which ones, except for the DAR National Library in
Washington and Lloyd House in Alexandria, VA).