C.S. Lewis and Darwinism

From Alan Jacobs, The Narnian (HarperOne, 2006)

from a letter to his father in 1925, p. 120 (long before he became a theist (1929) or Christian (1931), on having been accepted for English rather than philosophy.

If the air on the heights did not suit me, still I have brought back something of value. It will be a comfort to me all my life to know that the scientist and the materialist have not the last world: that Darwin and Spencer undermining ancestral beliefs stand themselves on a foundation of sand; of gigantic assumptions and irreconcilable contradictions an inch below the surface. It leaves the whole thing rich in possibilities: and if it dashes the shallow optimisms it does the same for the shallow pessimisms.

It's not clear to me why theistic evolutionists claim Lewis as one of their own. He never was.