OK! I found out through the fantastic Ellis Island website that my great grandfather Isidor Marcus (age 21 at the time) came with his brother Bermann (age 23 at the time...) ostensibly to live with their sister Rosa Marcus in New York... They arrived in September 1902 on the ship La Gascogne. The ship's manifest lists their occupations as "tailor" and their city of origin as Jassy, which is also spelled Iasi and Yassi. My mom says Isidor had six brothers... but only the two of them came on this ship.