Doyle,
You are correct about Perrin's brigade administering the "knock-out punch" to the Union First Corps, just as Scales' brigade was smashed on their left by combined infantry and artillery fire (the latter notably from Battery B, 4th U.S.). Perrin's breakthough was near the Seminary. The irony is that had this last charge not taken place by Scales/Perrin, more of the First Corps might have been bagged by Early's division which was then driving in the Eleventh Corps north and east of town, and even Rodes' division (Ramseur's brigade) coming in from the northwest. For an all too brief moment the rebels extracted their revenge on the retreating federals. Now Reynolds was an excellent general, but I don't see how his First Corps could have done any better had he remained alive. For me the most impressive Union command there was Stone's small brigade, which by adroit maneuvering toward the north and west near the pike held off superior Confederate forces for three hours. But again it's hard to visualize all of their movements around the cut and pike unless you have detailed battle maps showing the ebb and flow of battle. This by the way is a cut further west than the cut made famous by the Sixth Wisconsin versus Davis' brigade. Yet the former cut is not easily accessible and is virtually ignored by visitors, just like Perrin's successful attack on the ridge, and so visitors only experience a portion of the story, and a rather confusing and jumbled one at that. Tom