Thank you, Earle, for your reply to my inquiry. I think we're talking about different Arnold Peckham's, however, as "my" Arnold was b. 1776, so could not have had a first marriage in 1771. Unless, of course, the S.F. Peckham Genealogy has the information wrong for this family.
I will send an e-mail with more details and a request that you try to match my info with yours, to see if we can find a connection. Thanks again!