From Finest Kind's new cd, For Honour & For Gain, FAM09: 2010. (Oooh! Gotta get it!)

Their harmonizing style is undoubtedly strongly influenced both by their interests in the English tradition, which is more likely to have 4ths and 5ths, than lots of 3rds the way bluegrass, for example, does, and also in shape note music, which uses an older/weirder sort of harmony (with the melodic bass, random alto, and crossing lines that Ian pointed out) that is different from the more modern (since mid-19th century) moving triads of church or glee style.

~ Becky in Tucson