I have been to this place before, parking on the street to the west, Highland Street.But this time I looked at the map before picking a direction, and decided to head for the low lands. I thought I would go around the "Water Tank" hill, counter clockwise, and started out heading down into the gully south of the hill, where I saw a first sign of ceremonial structure:Was this deliberate? Here is another view over the structure down to the little brook forming there.Actually a gateway opening towards the water, or a blocked gateway like this, is a typical structure where water comes out of the ground.
Continuing downstream, I thought I saw a rock pile at the foot of a tree and, stepping over a log to get there, stepped right onto a rock pile.And then as I looked around I found a number of others. Most of them were oval ground piles. I found maybe 11 of them, scattered around underneath the trees:Here are two of the nicer examples.All of these piles are in a flat area at the foot of a hill (the "Water Tank" hill) with brooks coming in from the north and west - to either side of the hill. Places likes this where brooks meet, at the confluence of brooks, are a common place to find rock piles. Such a site was mentioned recently by TheSeventhGeneration [see also here].
Although these piles are somewhat "grave-like", there are a couple of reasons I do not think so. Firstly, putting graves near a water supply does not make good sense. Secondly, no quartz. Also those gateways.