There are a series of Ribble Valley Geotrails available on the internet and Walk 6 is at Long Preston, which we made our August outing. The walk starts on Green Gates Lane and from the top there are good views across the flood plain over which the River Ribble meanders. When the Valley is flooded it gives a good impression of what it probably looked like at the end of the last glaciation. Visible are low morainic hills, river terraces, and peat deposits. We walked over to the confluence of Long Preston Beck and Brook Gill Beck, both of which are glacial meltwater channels, and there is a large sand and gravel deposit between the streams. There is a noticeable difference in the vegetation on this deposit compared with the surrounding moorland.
We then walked east along Langber Lane and dropped down Newton Gill. In the stream bed it is possible to see the contact between the base of the Pendleside Limestone and the underlying Worston Shales. The limestone
consists of coarse rounded limestone fragments (clasts) and is known as a conglomerate. Within 100 metres or so the clast size varies from the size of a pebble to tens of cubic metres.
There is a small cliff on the south side of Newton Gill Gorge in which the sandstone mudstone couplets are turbidites. In this location the turbidites are ‘event deposits’, underwater avalanches often arising from an earthquake. Finally we briefly visited a limestone outcrop claimed in the guide to be a boulder, part of the Pendleside Limestone conglomerate. There was some scepticism amongst members of our group.