There is absolutely no doubt that Disney deliberately decided to attribute a square jaw to the heroine of their motion picture "Pocahontas".
They studied square jawed women from every angles and came to this beautiful virtual beauty.
I have seen in real life some women with this rare type of jaw. It's a very specific type of square jaw, only found on some asian women, and is my absolute favorite: face is jaw centric: it seems all the head is built around this pressure machine. Jaw is extremely square, muscular and strong, yet face is delicate and feminine. Jaw line is ruler straight, teeth are naturally perfectly aligned, broad and thick. Cheekbones seem very high and projecting, face is flat, forehead small, which gives a distinct aspect to the projecting jaw box. The straight hairs with small volume emphasis the face size and structure.
I think this site deserves a jaw classification chapter :) .
Pocahontas really existed: http://en.wikipedia.org/wiki/Pocahontas but we don't know if she was square jawed ;)