The indians head, dont forget, is only approximately 800ft across.
Yes this is a large mound, but not anything that could not be achieved with basic knowlege of 'setting out' and surveying.
it is impressive and too well sculptured in my opinion to be natural.
Also there are settlements and road networks all around.
GREAT SITE AND GREAT THREAD THE WORLD IS AN AMAZING PLACE!
AJA