In Gregory's THE SOUTHERN DIASPORA P. 64 HE DECIDES THAT AFTER ALL THE MIGRATION OF POOR FAMILIES IN 1935 WAS "FROM THE SOUTHERN PLAINS STATES OF OKLAHOMA, ARKANSAS, AND TEXAS."
Arkansas in the Great Plains? Really, in the Great Plains or Southern Plains?
But on 29 he refers to the "western South states of Arkansas, Oklahoma, and Texas."
Arkansas is by no stretch of the imagination a western state, but it can be considered one of the most western states of the South while still being a state in the central United States.
"Western South states" is not inaccurate. "Southern Plains" for Arkansas is absurd.
I belabor this because Gregory never seems to understand who the migrants to California were, who their parents and grandparents were, any more than Steinbeck did.
So Arkansas in AMERICAN EXODUS was populated by southwesterners and in THE SOUTHERN DIASPORA by inhabitants of the "Southern Plains" or the "western South." Take your pick.