In mixology, what is floated on top of a screwdriver cocktail to turn it into a Harvey Wallbanger?

The standard recipe for a screwdriver is two parts orange juice and one part vodka. The standard recipe for the Harvey Wallbanger is six parts orange juice, three parts vodka (thus maintaining the 2:1 ratio of orange juice to vodka), and one part Galliano. In a screwdriver, the OJ and vodka are stirred together with ice. To make it a Harvey Wallbanger, the Galliano is floated on top.

Most likely, the drink was invented by someone at or working for the McKesson Imports Company. Galliano is made in Italy and imported into the United States by McKesson. To promote use of the liqueur, McKesson paid a graphic artist to create a mascot for the drink, in the late 1960’s. By the early 1970’s, the Harvey Wallbanger was popular enough to make its way into the May 31, 1971 issue of “Sports Illustrated” magazine.

Donato D. “Duke” Antone is said to have invented the drink at his Blackwatch Bar in Los Angeles, California and naming it after a local surfer named Harvey, in 1952. That story is from the late Mr. Antone’s April 15, 1992 obituary in the “Hartford (Connecticut) Currant”. Mr. Antone served in the US Army in World War II and was retired from the position of headmaster of Hartford’s Bartending School of Mixology. However, no record can be found of a Blackwatch Bar in LA, and Mr. Antone was living in Hartford in 1952.