Just working through the Bland line of mine and though Catherine's line is interesting, I think that page 17 of this 1996 newsletter sheds some light on the reason there is a jump in dates between the first two children and the last (though as we know, sometimes unnamed daughters are scattered throughout). https://blandheritage.org/wp-content/uploads/2020/07/ACV14.pdf
I think that James Bland (my ancestor) and Robert Bland I are the son of William Bland, Sr. and "unknown 1st wife of William Bland, Sr" not Catherine Bland .
I have added source and/or information to as many profiles in that Bland group as possible as most had nothing. Catherine needs more and I will look for her. Any thoughts or assistance would be appreciated, including other information out there. The Bland book that the newsletters were based upon or connected to in not in print or I would order it.