I zoomed the images. Take a look at the relationship of the roads/paths and the "letters/rectangles." In many cases, the roads go THROUGH the rectangles. This tells me that there are no structures there and that the figures are clearings and are level ground -- not structures or pits of any kind.

IMO. this militates against the figures being cranberry fiels or any sort of mining activities.

__________________
Standing on the shoulders of giants...