The giant image and an elongated skull was found, It was of ancient ‘Aztalans’ that occupied Illinois, USA.
The size of this skull is more larger than average. This skull has a large hole in the jaw, typical of elongated skulls. It seems to have a unique and well defined skull pattern. Also this skull seems to have the largest mastoid-process i have ever seen. The information on this skull is limited. Though you may be able to find more information in Ancient American Magazine or this book Crania Americana.
Chris L Lesley