I'm almost certain that Riverside Drive was never known as "Boulevard Lafayette." I don't remember seeing reference to this in either Peter Salwen's Upper West Side Story or Clarence True's Riverside Drive. When the modern street opened in 1890 it was officially "Riverside avenue" and was renamed "Riverside Drive" a few years later. The "Boulevard"--the name for Broadway above 59th street until 1899--was only two blocks east of Riverside. "Broadway-Lafeyette" is also the name of a modern day subway station in downtown Manhattan. Perhaps this is the source of confusion? Jim Epstein