This is an excerpt that covers William Gregg and his son John Henry. The entire book can be found on Internet Archive.

• ...Footnote: "One William Gregg of Toberhead Mtg., and Ann Wilkinson, of Antrim Mtg., County Antrim, were married at Antrim, 11 Mo. 5, 1702…" NOTE: this is obviously a different William as the year of marriage is after "our" William's death

• The Caledonia is sometimes mentioned as the ship William came over on...I cannot find this ship in available lists. It is more likely he arrived on the ship Welcome (aka William Penn's fleet), which arrived in DE on 27 Oct 1682, & Chester, PA on the 28th.

• Date is just a guess based on son, John's year of birth. NOTE: The somewhat common belief that William's wife was Ann Wilkinson probably originates from a careless reading of the footnote on pg 319 of "Immigration of Irish Quakers by Albert Myers"...