Tom,

Your question is a good one, but difficult to answer accurately. Most of the work that has been done to document and categorize the barns of America is conjectural at best. Although it is possible to classify barns according to types and forms which indicate their origin, the truth is barns are utility buildings built for farmers by American carpenters.

John MacNamara of the "hidden mountains" area of upstate Pennsylvania is a one of many strong voices currently asking for a broader range of categories which includes Ameriacn barns and their variants. He's probably right.

I recently enjoyed a conversation with Bob Ensminger (The Pennsylvania Barn, Johns Hopkins Press) and asked him this question (yours). He is not aware of the swing beam existing in any barns he has visited in the old world. He further hesitated to categorize the swing beam barn as German, Dutch or English.

He did bring up an interesting point in reference to your historian's mistaken identification. It would appear that many people fail to differentiate between the Dutch barn (imigrants from Holland and the Netherlands) and the Duetch barn (imigrants from Germany and Switzerland). Geographically these areas are not very far apart, but there is a great difference in the barns they built and the vestages of them we see in our historic agricultural architecture.