 There are good examples of horizontal water mills , also known as Norse or <unk> Mills , around Dutch Loch . Originally these were two story buildings with turf roofs , built into banks to give access to the upper floor where the mill @-@ stone was sited . Inside the building there was a fixed lower <unk> , and a rotating upper <unk> driven by the water falling onto the <unk> below . Some were still in use on Papa <unk> in the early years of the 20th century , and there is still a working example of one of these mills on the Burn of <unk> , at <unk> in the south <unk> of Shetland . 
