A close look at the surface of a small mound

Saw this one from my car on the left, heading north on Ringe Rd just past West Ashby Rd.

This one is built into a boulder or outcrop (view back towards the road):

Look carefully at the upper surface:

I see some structure there. Let's assume it has not been disturbed too much and look at the details. Trying to highlight them:

I see a line of rocks (in red), a U-shape (in yellow), and a cup holder (in blue). Referring back to the first picture, isn't the "cup holder" interesting? [I imagine a bit of food for the journey to the underworld].
Uphill along the near horizon:

 

There were extensive small piles up there along the edge.