I have a pretty good genealogy, especially for MD. Happy to send it to anyone. It is on FTW.
The leading edge is:
Chew may be a truncated name.
I know of no documentation as to the birthplace of John Chew of Jamestown. The whole Somerset business may be baloney--probably because Chewton and Chew Magna sound so good for the purpose. I can tell you this: I was in Chewton and the parish records indicate that there was never a Chew in Chewton.