I dunno craig matey!
When dealing with pre-history, you can't write anything off. These features may be purely and simply erosion. the stones may have been chosen for these features. The features may have been elaborated to receive libations (is that the right word?) there is a scottish tradition of pouring milk on the stones to ensure the fertility of a cow.
Our ancestors probably had similar esthetic values to ourselves. Pecking out a natural fault or bedding plan to accentuate it would have the desired effect and increase the rate of erosion. Who knows the secret of the tall tragic rocks? not I.
love
fitz