Briefly the tradion is identical to that found in my own area of Sheffield and N. Pennines (UK) and was carried over there in 1848. It still exists and the story is well documented. We in Sheffield were really privileged to have a visit from them 2 years ago (since they rarely travel) to the Festival of Village Carols, Grenoside, Sheffield U.K. This is held every two years and this year's (November 27th) is already sold out.
Dirty Linen+Glenrock into google will also get you an article about them.