Prince Edward Island is located in the Gulf of St. Lawrence west of Cape Breton Island, north of the Nova Scotia peninsula, and east of New Brunswick. Its southern shore bounds the Northumberland Strait.The coastline consists of a combination of long beaches, dunes, red sandstone cliffs, salt water marshes and numerous bays and harbours. The beaches, dunes and sandstone cliffs consist of sedimentary rock and other material with a high iron concentration which oxidises upon exposure to the air. The geological properties of a white silica sand found at Basin Head are unique in the province; the sand grains cause a scrubbing noise as they rub against each other when walked on, aptly named the singing sands. Large dune fields on the north shore can be found on barrier islands at the entrances to various bays and harbours.