C. S. Lewis on Theistic Evolution

I just ran across this passage in The Problem of Pain. In this chapter Lewis gives a tentative explanation of how the fall of man could have happened, and how human beings, as God's image bearers, could have been created.

"I offer the following picture - a 'myth' in the Socratic sense, a not unlikely tale.
For long centuries God perfected the animal form which was to become the vehicle of humanity and the image of Himself. He gave it hands whose thumb could be applied to each of the fingers, and jaws and teeth and throat capable of articulation, and a brain sufficiently complex to execute all the material motions whereby rational thought is incarnated. The creature may have existed for ages in this state before it became man: it may even have been clever enough to make things which a modern archaeologist would accept as proof of its humanity. But it was only an animal because all physical and psychical processes were directed to purely material and natural ends. Then, in the fullness of time, God caused to descend upon this organism, both on its psychology and physiology, a new kind of consciousness which could say 'I' and 'me,' which could look upon itself as an object, which knew God, which could make judgements of truth, beauty, and goodness, and which was so far above time that it could perceive time flowing past."
- C. S. Lewis, The Problem of Pain, ch. 5, "The Fall of Man"