Thanks for clarifying that. Considering HN's worldwide readership, I should have anticipated that misunderstanding when I posted the quotation. I have now added "[= indigenous Americans]" above.
I would have thought the war parties of the great plains would give it away.
My bad. I too should have considered that the term "Indians" is ambiguous and should have looked up the reference book. Thought the title "Great Plains" was referring to plains including the Indo-Gangetic plain.
Is "East Indians" the commonly used name in the US for the people of India ? I've come across "Asian Indians".