Barbara - I'm researching the exact same thing. My great grandfather was Earl Letts (from South Amboy)...and he always told us that someone in his family line was an Indian Chief. I just started researching the Letts line and my great grandfather's line goes back to William Letts from Holland Netherlands that was born 1642 and died in 1701 in Perth Amboy. Knowing they came to the US in 1642 and settled at the time in Elizabethtown, East Jersey...made me start to research the Navesink Indians (Lenape tribe) because they also settled in the same area as well as South Amboy, Perth Amboy, Middletown, etc. I wonder if it could have been possible for a dutchman to join the tribe. I haven't found any connection to Willard T Letts yet...but maybe my thinking is wrong and possibly Wllard is related somehow to our line of Letts and was the Indian Chief. I would love to know if you find anything out and I'd be happy to share with you to. My email is email@example.com
Good luck with your search...it would be great to find that we are related to a Native American Indian. I can tell you that I truly believe that story we were always told. My mother's family was 100% Danish/Dutch - yet my younger brother looks Native American (olive skin, dark hair and dark eyes)...and the rest of us are blonde and blue eyed. That is one reason we always believe that oral family history of the Indian Chief.