Jamaica's Heptones built their formidable style around ‘60s-era rhythm ‘n' blues and their native roots reggae. It was a mash-up that never grew dull: The beach-ready “Mr T” infuses sunshine dub with retro-soul harmonies, and their lowrider-oldies covers such as “Sea of Love” and “Crystal Blue Persuasion” bring a tropical-minded sensibility to songs made legendary by Motown royalty.