U. S. Grant's Mayflower lineage to Richard Warren of the Mayflower is given very clearly on pp 37-39 of "Ancestors of the American Presidents", by Gary Boyd Roberts, 1995. An abbreviated form of the same is on pg 336. This is an excellent book for finding relationships to US Presidents. I highly recommend it. It is published in cooperation with the New England Historic Genealogical Society, Boston, Mass. I never knew I was related to any US President until I bought this book and spotted many of my early New England ancestors in it as also being ancestors of many US Presidents. Exciting! Marty Irons PS: For what it's worth, Gary Boyd Roberts shows U. S. Grant's original name as Hiram Ulysses Grant. Presidents Ford and Clinton also changed their names.
This may be somewhat off-topic, and I apologize ahead of time if it is, but I had heard on I believe an A&E presentation that as a cadet, Hiram Ulysses Grant appeared before the army recorder and when he was asked to state his name for the record he said Hiram Ulysses Grant. The recorder in error thought he said "I am Ulysses S. Grant" and recorded it that way. Rather than making waves the very first day to correct this error, Ulysses decided to keep his name the way the army recorded it.