[blam]

Sounds like these could be some of the folks Schoch speaks of in his book, Voyages Of The Pyramid Builders. In this book he speculates that all the cultures of the pyramid builders originated from the Sunda-shelf and these people spread around the world (as the 'shelf' went underwater) taking pyramid building with them, as far away as Egypt and South America.

I'm beginning to think there was a worldwide trade network in prehistoric times and that any part of the network may, or may not, know of the lands where some of the traded goods originated. This could explain how coca leaves (apparently) end up in Egypt and must have been very expensive. These trading links would break and re-establish at various times.(?)

Some of the South American natives have a 'Chinese like' attraction to jade.

[Fedora]

Some of the South American natives have a 'Chinese like' attraction to jade.

That is one thing that strikes me as a big potential clue: if it were possible to establish any cultural and/or chronological correlation between jade art styles in China and America, it might help pinpoint when cultural exchange may have occurred.