Sailor's grave

Well at least for some time that is what I thought these rectangluar piles of stones were on the shore. In fact they are the remains of kelp kilns where seaweed was burnt to produce material for processing to create a variety of chemicals.
At the boom time of this industry in the early 19th century, it was by fasr the most profitable activity that the landlords could pursue and changed the whole landlord-tennant relationship for ever, effecitvely leading to the clearances later in that century.