What the fork?

Through the good offices of Netflix, I have been watching the excellent HBO series John Adams. For such a well-done production, I know the clothing and house furnishings must have been meticulously researched, but one scene raised a question.

The indomitable Abigail Adams is at a high-tone dinner party and she is shown eating in what is known as the continental or European manner, i..e., fork in left hand, tines down. Was this the way colonial Americans dined? If so, when did American manners evolve into what Emily Post called the "zigzag" manner, cutting with fork in left hand and knife in right, then switching the fork to the right hand for the trip to the mouth? (I assume right-handedness not only because "Righties Rule," but until relatively recently in our history, lefties were required to use the right hand at table, regardless of the awkwardness involved.)

This question has proved difficult to answer. According to Wikipedia, it was not until the 18th century that forks came into common use in England. The modern curved-tine fork was developed in Germany in the mid-1700s. That's really close to the time period in question.

According to Margaret Visser in The Rituals of Dinner:The Origins, Evolution, Eccentricities, and Meaning of Table Manners, an American etiquette book published in 1837, still conditionally approved eating with a knife, the everyday manners of many centuries standing. In continental Europe, on the other hand, a fashion arose in the 19th-century for the zigzag method. Perhaps to distance themselves from the effete French, the English went to the fork-in-left-hand method that soon crossed the Channel and conquered the continent.

Americans kept on with their zigzag eating, representing a survival on our shores of older English ways. (The word "gotten" is another. The English long ago gave it up, preferring "had got," but that development occurred after the great rupture separating our two cultures. So Americans hang onto a relic of Middle English.)

So, did Abigail really eat as shown in the miniseries? I doubt it, but I don't know. If I ever make it to Colonial Williamsburg, I know what question I will ask.