We had seen on the map of Jura that there is an impressive glacial feature on the west side of the Paps, the inaccessible side. So I was really pleased that the feature was really obvious from the ferry to Colonsay. It is a long straight line of rocks over 2 mile long making its way down the hillside. It runs diagonally down the middle of this picture.
In the picture below it is clear that it is more than one line.
https://www.geograph.org.uk/photo/4983084 has a picture taken looking down the line of the rocks from the hillside above and explains the legend. My Gaelic dictionary gives one translation of sgriob as "furrow". The double line looks a bit like that.
http://jncc.defra.gov.uk/pdf/gcrdb/GCRsiteaccount979.pdf has the full explanation. It is thought that the peaks of the Paps poked out above the ice forming nunatak peaks. The glacier split to go round them and where the glacier recombined, rocks were dropped in a long line. It is remarkable that over 10000 years later it remains uncovered by vegetation.
