So after viewing one of my cities and seeing it was providing over a 50 constitution  I quit the game and reloaded to find it increased by the value of the enchantment yet again! Also I discovered the limit to the bonus from these auras is 96. I demand you remove this uncalled for limitation!!

Uhh seriously though this is a pretty big issue. Not to mention the earth spell (Aura of Might) shows up in the spells list but does not have any spell level requirements, nor does it ever become available. Either this was decided to be too powerful and the heirgamenon wasn't updated or it wasn't properly linked with the earth spell school.