I'm searching for some clues to who is Carl F. Greenway. My Great Grandmother was Martha E. Petty Childers. Daughter of William and Eliza Petty. Martha was born in 1852 in NC with other siblings. In my Grandmothers cedar chest was this piece of paper with this name and sentence.

Carl F. Greenway
950 Fifth Avenue
New York 21
N. Y.
I am Martha E. Petty Childers grandson.

My Great Grandmother Martha married Jack Childers in NC and moved to SC. Is there anyone that might know who this Carl is and the connection between my Great Grandmother?
Thank you very much.