This was one of the most interesting buildings I think I have ever been a part of dismantling. What he web site doesn't show is that it was a "ground bound" building in that it had no sills, just a HUGE lower girt that was half lapped into the posts and pegged. The tie beams all were tapered as were the plates. It looked as if they simply squared up the trees and used them as is. If I remember right, one of them was very curved. Some of the purlins were straight, some curved. All of them were hewn flat on one side. Also, if memory serves me right, most of the frame was oak and chestnut. Whatever the species, it was really heavy.
Back to the original question. . .I do see a lot of common purlin roofs on barns and house from that era in that geographic reigon. Mostly on buildings before the 1760's. Also, in many cases, the purlins run the length of the building uninterupted.