Aperature piles are high built piles with a hole you can look through. One of the things Iearned this weekend is that you can see something through the hole; not in the sky but on the ground. See earlier posts for examples.Each one has a hole in it which I tried to show in the photos. In the above picture the hole is just at the end of the right hand fork of the stick leaning against the pile.
Note how these piles are built up tall and thin.
A really wonderful site, with lots of these aperature piles. All the piles had nicely built vertical faces although I do not think they all had aperatures.
Along one gully the piles were so thick you could eat them with a spoon.