I have a copy of an 1860 map of New York City that I got from the new york public library. It shows Marion st as running from grand st to prince st. parallel to and west of mulberry street. A little past prince street it dead ended. it may have run farther south then grand st. it may have run all the way to park place but the map is less clear about that. I think there is a reference work on manhattan street names and if i think of it i'll advise you. Jim Maguire [log in to unmask]