(If it is not apparent, I find the sentiment expressed by the late Mr Darwin repellent and sinful. The passage and comment come from Dembski’s The End of Christianity)
Thus, in The Descent of Man, the sequel to the Origin, Darwin noted,
At some future period, not very distant as measured by centuries, the civilised races of man will almost certainly exterminate, and replace, the savage races throughout the world. . . . The break between man and his nearest allies will then be wider, for it will intervene between man in a more civilised state, as we may hope, even than the Caucasian, and some ape as low as a baboon, instead of as now between the negro or Australian and the gorilla.
Just so there is no doubt, Darwin saw, as a consequence of his theory, that whites (whom he regarded as “superior”) would exterminate blacks (whom he regarded as “inferior”).