This may be of no help to you in case your Joseph and Mary were living in the times of 1850+ (the years of more detailed Federal censuses):
"Index to Marriages of Old Rappahannock and Essex Counties, Virginia 1655-1900" by Eva Eubank Wilkerson finds listed the year 1689 as an approx. date for a marriage between a Joseph Bragg and a Mary Tap (not Tapp).
This date is based on info that Mrs. W. found in Order Book 2, Page 177 in Old Rappahannock Co. (sometimes labeled "Old Rappa" and not to be confused with Rappahannock Co. in western VA) because that was the county's name until April, 1692. At that time, the county name was retired and the area became Richmond Co. to the north and Essex Co. to the south with the Rappahannock River dividing them.
The 1655-1853 marriage dates for the most part were estimated by info found by the author as she researched and indexed the court records--deed, will, order, etc. books--for "Old Rappa" and Essex counties. Marriage data after 1853 is found in marriage bonds and the Marriage Register (which is Book One) for Essex Co..There is no Marriage Register for the years prior to 1853.
Therefore, families in those counties assumably had many more marriages than are listed in this book, the only marriage book available for these counties from 1655 to 1853, thanks to Mrs. W.'s efforts.
I believe I read some where that during the WPA of the 1930's, Mrs. W., a VA farmer's wife, temporarily moved to Essex Co. with her 4 young children in tow so that she could work on indexing and cataloging the court records. (I assume this was a way to earn an income at that time.)So imagine doing all the work she did with having 4 children (and no computer!).I have often thought of that as I look through her book---wondering if she had relatives in the area to watch the children for her or if they accompanied her at times, anyway, and how did she ever keep them occupied as she read and perused over all those volumes of spidery handwriting!
I am descended from the Tapp Native American (Wicocomico) line which early on was in Northumberland, Co., VA.A set of my 3rd gt gpa were Mark and Nancy Tapp Landrum who wed in Culpeper Co., VA in 1786.