Yes he certainly did. But he ALSO said that the six days of Genesis were not actual days, but that the creation happened "simul" = "all at once", and that the six days are actually six sets of revelations to the angels.
He ALSO admitted the possibility that certain animals like flies were only created potentially in the first six days and actually arose later through the power that God had placed in the earth at Creation. Not quite evolution, but certainly a philosophical leap in that direction.
The point is that the subject of Creation is extraordinarily complex. Augustine sheepishly admitted in his book that he was asking more questions than he could answer, and he said that if a better interpretation could be found for some of his ideas, so much the better. We would all do well to be a little circumspect about it today--and not go jumping to conclusions about direct evidence for Noah's flood from one site in inner Mongolia.
Oh, and by the why, he was right to scorn the "mendacious documents" that purport to give many thousand years to the history of earth. Human memory is not that long.
Do you agree with Augustine in the areas where he departed from scripture that you outlined above?