Yes, this is a better reference.
That said, I can imagine that to a paleolithic hunter/gatherer it would be beneficial to use an arrangement of stones to "capture" a particular date. Dates of interest might be 'migration', 'planting', or 'harvesting' dates.
Setting up stones to cast a specific, and unique, shadow on a particular date is easy to do on that date. And I've done it on hiking trails for things like solstice dates for other hikers to discover later. Since the transformation of the shadow is predictable with motion of the Sun, I've also used it on trails where I experienced good conditions, so that when I come back to that trail, I can look at my 'date ducks' and they will tell me if it was earlier or later in the season when I set them up (assuming they haven't been moved of course).