I did not say that Augustine believed that the seven days were literal. However, he said on Adam and Eve, as I quoted before:
These and similar
allegorical interpretations may be suitably put upon Paradise without giving
offence to any one, provided we believe the truth of the story as a faithful record of historical fact."(Augustine, City of God, Book XIII.XXI )
Now Let's read Irenaeus:
But, in order that the man should not entertain thoughts of grandeur nor
be exalted, as if he had no Lord, and, because of the authority given
to the man and the boldness towards God his creator, sin, passing beyond
his own measure, and adopt an attitude of self-conceited arrogance
against God, a law was given to him from God, that he might know that he
had as lord the Lord of all. And he placed certain limits upon him, so
that, if he should keep the commandment of God, he would remain always
as he was, that is, immortal; if, however, he should not keep it, he
would become mortal, dissolving into the earth whence his frame was
taken. And the commandment was this: ‘You may eat freely from every
tree of paradise, but of that tree alone, whence is the knowledge of
good and evil, you shall not eat; for on the day that you eat of it, you
shall surely die’ (Gen 2.16-17). (The Demonstration of the Apostolic Preaching, 15)
The above words clearly show that Irenaeus believed in a literal interpretation of the account of Adam and Eve.