With careful sleuthing I was able to find several locations where there were alleged burnt areas this one allegedly leaping the nearly impenetrable Brentville perimeter. This is un-retouched, on the scene, almost live coverage.
Another view of what is left when you let the smoke out of the grass.
To summarize what I learned by this experience: 1. I found no mirrors so it might have been real, 2. NEVER go on a bike ride (or is that cycle ride?) no matter how close to home with out some tools. The chain broke and with no way to affix the dangling ends I had to walk home. I hate it when that happens.