Darwin believed some human 'species' were superior than others!

de bene esse: literally, of well-being, morally acceptable but subject to future validation or exception

Charles Darwin entered the world over 200 years ago when slavery existed and racism was a dominant theme worldwide. Darwin is known for his Theory of Evolution but few actually know that Darwin was a racist, despite being against slavery.
Darwin believed that all men were brothers and should not serve as life-long slaves. However, Darwin did not believe all men were created equal and that some races (or human 'species' as he called them) were more superior than others.

Any non-white person was classified as 'savage' by Darwin as he insisted that Caucasians were more evolved and that other 'species' of humans would be eradicated because they would be unable to adapt to the advanced lifestyle of Caucasians.

Where does he say this? In most of his published books including, 'The Origin Of Species,' his most famous. Darwin discussed that his theory of evolution can be applied to the development of mankind