Here is another website about heraldry which has several bookplate postings
William Griffitts bookplate is extremely rare and not is listed by Charles Dexter Allen in American Bookplates
"Fig.920 is another example and copies from a very artistic copperplate etching used by the Griffitts family of Philadelphia,who are of Welsh descent. Its continued use suggests its genealogical value.Thomas Griffitts emigrated to Jamaica ,West Indies,1714 and in the year following to Philadelphia engaging in trade with the first Isaac Norris,whose daughter Mary he married in 1717.He was Keeper of the Great Seal of Pennsylvania from 1732 to 1734, Provincial Councillor,1733.Mayor of Philadelphia 1729-1733-1737,Judge of the Supreme Court from 1739 to 1743.He died in Philadelphia 1746.
William Griffitts, born 1724 was one of the founders and earliest contributors to the Pennsylvania Hospital.He married ,April 16,1752,Abigall, daughter of Samuel Powel and died at Philadelphia August 25, 1762"
The bookplate was used successively by Thomas , William, and Dr. Samuel Powel Griffitts from 1714 to 1826.
Ref. P 324-326 Heraldry In America by Eugene Zieber
I defer to my English collector friends on all things related to heraldry.There is some question about whether the Griffitts family is of Welsh descent.
Those of you who live near Brooklyn , New York may want to visit the Brooklyn Historical Society to see the
Emma Toedteberg bookplate collection. I plan to see the collection in late March.
On Friday Evening March 2nd I will be visiting the Washington Antiquarian Book Fair.
Nothing else to report. See you next Sunday .