Pete, Do you know of a book titled The Ryerson Genealogy: Genealogy and History of the Knickerbocker Families of Ryerson, Ryerse, Ryerss; also Adriance and martense Families; all descendants of Martin and Adriaen Reyersz (Reyerszen), of Amsterdam, Hollan, by Albert Winslow Ryerson? It was privately printed for Edward L. Ryerson, Chicago, 1916. This book is available from Higginson Books (http://www.higginsonbooks.com/) for $69.50. While there is not much about your Theunis in this book, he is there (notice that Tunis is a spelling variation for Theunis) and thus is connected to this family. He is listed as 7th generation from Martin Reyersz and is listed on page 207 as the second child of John Rappelie Ryerson and Martha Steele. All that is noted about him is that he married a Rose A. Anderson. His older brother was Samuel, b May 29, 1826; m Ruth Howell, who was b Dec. 1827. The youngest child is Jane, m a Mr. Bennet, living in Michigan. The father was born in New York City Aug 14, 1805 and he died Mar 12, 1875. Resided in Paterson (I don't know where that would be). I had hoped that the book would have had more information about your Theunis.