"Cowper" (168) and "Delight" (216)
This (Sacred Harp or Original Sacred Harp/OSH) is the source of gospel music. It derives from the New England Singing School, transmitted down the Southern mountains. That in its turn derived from the West Gallery choir music of rural England, that grew out of the old Tate & Brady psalmody.
Great film about the tradition is "Awake My Soul" - here's the trailer. Best line: "They asked, 'do you want to sound like a bunch of uneducated Southerners?' We all said . . . 'Yeah!'"
It's pretty raw in performance, but it is actually very sophisticated music. The classic signature "fuging tune" (when you hear the parts in imitation of each other a few measures or beats apart) originates even further back - in early Renaissance polyphony. Everything new is old.