Streams of stones 

by Bill Baird

The stone runs of the Falkland Islands have been an object of wonderment to every traveller who has seen them since the time of Pernety. Darwin, 1839 describes these ribbons of great angular blocks Iying in the bottoms of many valleys as "streams of stones". These sharp unweathered blocks of quartz rock range in size from blocks a foot or so across to boulders the size of a house. In some places the streams occupy that position in a valley normally occupied by a river while in others they lie on the hillsides even running to the tops and crests of the hills. Explanations for the occurrence of these stone streams have been many, including earthquakes and glaciers, but present theories suggest a periglacial origin allied to the nature and bedding of the quartzose parent rocks. 

References 

Darwin, C., 1839. Geology and Natural History of the various countries visited by H.M.S. Beagle, 254-256, London. 

Joyce, J.R.F., 1950. Stone Runs of the Falkland Islands. Geological Magazine, Vol. 87, No. 2, 105-115.