Jah, like you said, I realise we have to take 'their' word, as were not the 'specialists', Not sure how you'd date a crack (hey there, now then, now then!) as over thousands of years all sorts of dirt, debris etc... could have accumulated there. Plus the nature of the stones vertical planes, ice and water ingress into the fractures are likely to have caused significant fall off's and erosion from the original quarried face. Still, I like that they are trying to push our knowledge forward, even if the theory turns out to be hokem. And on the bright side, they found some sort of encampment at least, at least according to the press, and the charred hazelnuts.

As to telling which stones is fer monument building, and which is just clitter. Before the archo's settled on Carn Geodog as one of the bluestone quarries, it was Carn Menin I think they thought the bluestones were quarried from. When I visited many years ago, every 7 foot stone pillar partially buried looked like a possible Stonehenge contender. Still. Had a wonderful day hiking and clambering about, so whatever the outcome, it wasn't wasted.