Stone wall features

There is a stone wall that runs up and down the hill near the boulder field. I'm not certain if it has any significance to the boulder field or if it is colonial, but it has a couple of nice features to it. One is a small aperture:



The other was a nice 'wave' to it that looks somewhat snake-like:





This rock wall goes down to the area where 3 rock walls come together to form a channel, but don't appear to meet. I can't help but think it might be a sheep weir or a deer weir. But I question whether a deer weir would be found so close to the large cairn site that seems to have some spiritual significance related to the headwater. The headwater is to the northeast of where the stone walls come together, about 2/10ths of a mile away, and the large cairn site lies between the two.