The Falklands stone runs are made up of hard quartzite blocks. They are more widespread and larger on East Falkland, especially in the Wickham Heights area where the largest of them extend over 5 km in length. Those on West Falkland and the minor islands are fewer in number and of smaller dimensions. Darwin's great valley of fragments, subsequently renamed Princes Street Stone Run after Edinburgh's Princes Street that was cobbled at the time, occupies a 4 km long and 400 m wide shallow valley trending east-west. The feature is situated off the road to Port Louis, some 20 km northwest of Stanley.