This author does have it right in that the West was Southern. As was the mid-west, Illinois below Chicago, southern Indiana and Ohio.
I would disagree and say it was much more of a melting pot than New England.
It was not just Scots Irish but German and Dutch, free black and mixes of white, black and Indian such as Melungeon who settled Tennessee, western Virginia and southern regions that were the first west and forebears of the west.
Ummmm...
Turns out the Melungeons aren't really Indians (or Turks as some of them claim).
Melungeon DNA Study Reveals Ancestry, Upsets 'A Whole Lot Of People'