What is with all the elongated cross-bar rocks?

In the previous post, the 3rd, 5th, and 6th pictures show piles with an elongated rock across them. In the 3rd picture it is pointing towards the camera and in the others the view is from above. Here is another. Note the larger rock to the left which is what I am calling a "cross-bar". I associate such structures with effigies where, the elongated rock is supposed to be a pedestal for the figure. That may not be valid here but many of the piles on this slope have the feature.

Looking through the pictures I took, here is another:
and another: