Large Propped Boulders on a Hill

As I review my vacation photos, it  becomes striking how often propped boulders are found in the Southwest as well as the Northeast.  Manitous are common in RI, where the granite breaks into slabs, but are rare in the Southwest, possibly because the stone there does not break into slabs.  In the Southwest, there  are also very few rock piles or cairns, and few stone rows.  Since there is no apparent agricultural use for propped boulders, it is safe to say they were constructed by Natives and not settlers.  The location of the propped boulders may give a hint as to their significance.  In RI, hilltops are often crowned with boulders left by glaciers, but only certain boulders are propped.  Here, for an example, is a hilltop with two large propped boulders.
Here are two views of the first:

In this face,  the carved out areas along the lower edge are obvious.

Another angle, and some more views.

And here is the supporting rock.  That is a shadow of my fingers to the right. I am trying to keep them from straying in front of the lens.

And about 50 feet away is this boulder.

Here is the underside, showing that it also has had chunks of rock removed.

These two boulders, like many of the other propped boulders, are resting on bedrock.  Also, they are on a direct N-S alignment.  The directions were sacred to the Natives, so maybe this was a factor in choosing which boulders to prop. Two of the boulders in another site I showed previously (3/14/2012) are also on a nearly N-S alignment.