1671 John Lederer
This circle is a consistent  cartographic representation of “the Island,” Although it more closely resembles the Langstrom Map being to the side rather than in the middle of the river as in  the 1700’s Fry series.
1751 Fry
1781 Chesnoy
1755 Vaugondy
1662 Langstrom
http://www.charlescity.org/natives/images/1699.jpg
I did find a different versions of the same Lederer Map, and in this one the circle has a dot inside similar to other Indian Village designation on the map.