No i've never read Graham Hancock book America before. Hancock seems to be on the right track on the history of the world.
From what I heard of him he doesn't go far enough.
On this video he explains at 31:30 there was a land bridge between south America people and Polynesians. Also some of the Māori people in New Zealand have red hair. I say he doesn't go far enough. Look at google maps the oceans between Brazil and the French Polynesians areas in the south pacific.
Those are stretch marks that had to have happened not that long ago. The oceans would've washed most of it away if it was over millions of years. India coming from south Africa all the way up to where it is today. More stretch marks. Why do they "assume" it took place over millions of years?
My idea is that the continents are floating on magma. Where ever the plumes are is where they're going to move during the Heinrich event.
America Before: The Key to Earth's Lost Civilization
https://www.youtube.com/watch?v=GAccZ8eWhXo