A sentence on how the canyon came to be, geologically speaking, would not be amiss.
Is the external image in accord with policy?
Construction
Unless I'm missing something, you never actually say what the building's made of nor how, in general terms it was constructed. There's much discussion of trees. Were logs used, or smaller bits of lumber? If the logs were used, how were they transported over rather difficult country? I see discussions of masonry and the images suggest that stone was used, but what do I know? If stone was used, was it local or was more suitable stone brought in from elsewhere if the local rocks wouldn't do? Roofs?
"regular annual intervals" this seems unclear to me.
"The population of the great house might have been large enough that laborers gathered structural wood during the agricultural season, or this might indicate that groups of Chacoans were dedicated to tree felling irrespective of the farming season, when most others were busy with field preparation and planting." If I'm reading this right, both alternatives seem to amount to the same thing: there were enough Chacoans that even during the farming season, they had labor they could devote to tree-felling.
