Another picture of the two stones, now looking NE.

The Cwm Garw pair of standing stones, 
looking NE

These are only one of several pairs surrounding the Preselis. The ordnance survey 1:25,000 scale map of the area reveals at least five others. To my knowledge pairs of stones are not particularly common, and I have not explanation to the significant cluster around these hills. E-mail me if you have any ideas on that or some other thoughts.