The following excerpt is taken from Augustine's The Literal Meaning of Genesis: An Unfinished Book, as translated by J. H. Taylor, S.J., Newman Press, New York, 1982. Although this work was written in AD 401, you will notice that Augustine's understanding of "literal" is quite different from today's notion of a "literal interpretation of Genesis" as claimed by young-earth creationists. On the contrary, you will see that Augustine was well aware of the teachings of "natural science" (such as it was), and was reluctant to contradict its findings, out of humility for the general revelation of God.
The Literal Meaning of Genesis
By St. Augustine of Hippo
Book 1, Chapter 19
38. Let us suppose that in explaining the words, "And God said, 'Let there be light,' and light was made," one man thinks that it was material light that was made, and another that it was spiritual. As to the actual existence of spiritual light in a spiritual creature, our faith leaves no doubt; as to the existence of material light, celestial or supercelestial, even existing before the heavens, a light which could have been followed by night, there will be nothing in such a supposition contrary to the faith until unerring truth gives the lie to it. And if that should happen, this teaching was never in Holy Scripture but was an opinion proposed by man in his ignorance. On the other hand, if reason should prove that this opinion is unquestionably true, it will still be uncertain whether this sense was intended by the sacred writer when he used the words quoted above, or whether he meant something else no less true. And if the general drift of the passage shows that the sacred writer did not intend this teaching, the other, which he did intend, will not thereby be false; indeed, it will be true and more worth knowing. On the other hand, if the tenor of the words of Scripture does not militate against our taking this teaching as the mind of the writer, we shall still have to enquire whether he could not have meant something else besides. And if we find that he could have meant something else also, it will not be clear which of the two meanings he intended. And there is no difficulty if he is thought to have wished both interpretations if both are supported by clear indications in the context.