" I would investigate why he changed his name from Kingman. I notice that the will was proved by his son Samuel Clerke Alias Kingman. Is there any mention in New England of that James Clerke also being alias Kingman"
He may have been baptised with that name. There are very many families in Dorset, ( adjacent to Somerset) which the registers record baptisms, marriages and burials as ___ alias ____ .
I have in my own family a branch from Northamptonshire which for a couple of centuries called themselves Caporn alias Fitzhugh (and just to confuse matters, sometimes they used the lot, sometimes they used Caporn and sometimes Fitzhugh. see also
https://www.familysearch.org/wiki/en/Use_of_Aliases_-_an_Overview (it's a bit of a bugbear of mine, I still haven't put this family on wikitree because of the difficulty in knowing how to record it in the data boxes.It's odd that no-one else seems to have come across it)