I'd suggest checking out the "Edward Jessup of West Farms" book; it's available printed on-demand or on CDROM.
I've seen some references to John Jessups in LI/CT that don't have dates that match with any of the descendants of the first John Jessup in America (1637 Wethersfield; a son(?) John helps found Stamford in 1641; another son(?) Edward is Edward of West Farms. There are a bunch of Jonathan Jessups, including two in a row (1707 and 1734, then Peter and another Jonathan 1761 and another 1795). I have two Isaac Jessups in a row, but they'd be Isaac, Isaac Knapp, Gershom, Jonathan (1734), Jonathan (1707), Edward (1663), Edward (of West Farms, b. 1624?? Leyden), John (1604???? England), Francis (*maybe*, I lean against lately), then the other Broom Hall Jessops.