Antecedent to the hobbit-hole?

Look familiar?  This is a replica of Erik the Red's home in Iceland, but you might mistake it for the home of a hobbit.  Apparently, the majority of homes in Iceland were made of turf well into the 20th century.  My ancestors came from Iceland and may well have lived in such homes.  In fact, when my great-great grandfather first came to America, their first home was a dugout with a turf roof.  Tolkien was a scholar of the Norse languages and cultures and one wonders whether the Viking turf homes served as inspiration for the dwellings of the gentle folk of The Shire.  You can learn more about Icelandic sod homes here:  http://thereifixedit.failblog.org/2010/09/30/historical-thursday-viking-turf-homes/