Second day of walking in Glen Roy. Had thought of doing a figure 8 walk to do the three red Corbett's here. Looking at OS map night before spotted the 'natural bridge' (NN 3685 9184) and decided that really was the logical route and needed to include. Involved crossing one river but Alfie was up for that. Beautiful day and although it's hard to tell the difference between the tops, the walk is in a magnificent area. Over the course of the day, I was able to explain the formation of the parallel roads to Alfie. Think he grasped it. Remarkable.