Again, Sander's highest support is amongst demographically white working class neighborhoods.
The Sanders portion in the middle under "west end" is Vanderbilt university (white in GOP second place map.) The southwest corner going for Bernie I find curious- though pretty rural so hippies- went for Cruz too.
The part above Cumberland River with "Eastland" is a very progressive part of town, no surprise. Bernie's swath to the west, above Charlotte, is heavily working class- near what used to be Ford glass plant- lots of streets named after Ford cars. The dark red above heavily African American.
The Trump- Rubio divide seems very class based, not surprisingly.
Theres a lot to assume from this but in Memphis and Nashville, Trump's highest support correlates with whites living in Black majority neighborhoods. I keep seeing this pattern all over again, Trump's highest support is whites who live in black belt counties in Alabama, Georgia, South Carolina, Virginia.