The stone wall (followed by the Coast-to-Coast route) is rich with fossils and I found a coral fossil.
Up on Smardale Fell the heather is spectacular at this season and if this were simply limestone country massed heather would not thrive, but the geology is complex. Limestone walls have gateposts of sandstone and as you approach Smardale Bridge there's a mix of rocks in the dry-stone wall. Sandy Bank shows on the OS map where there was a sandstone quarry directly west of Smardale Bridge and there are other disused sandstone quarries hereabouts. The double limekilns abut a limestone quarry rich in fossils. I think there's a niche floral habitat up on Smardale Fell, where there's a particular geology- but I cannot recall the detail.