In September for our final outing we walked the Sedgwick Geological Trail, and visited Dent. The walk begins at Longstone Common on the Hawes Road outside Sedbergh, at Danny Bridge over the River Clough, a tributary of the River Rawthey. In a distance of just 600 metres it is possible to locate the Dent Fault, and to observe how the Carboniferous rocks of the Pennine side of the Fault have been crumpled up against the older Silurian rocks on the Lake District side. Adam Sedgwick was the first person to observe and explain these geological features. Sites of interest are marked along the trail, 1 to 4 being on Asbian (338Ma) Great Scar Limestone with Rugose corals, brachiopods and several deposits of black Chert. Between sites 4 and 7 there is evidence of folding of the beds due to the closure of the Iapetus Ocean during the Caledonian Orogeny (400Ma). The Dent Fault (290Ma), which raised the Lake District hills to the west by as much as 2.5km relative to the Yorkshire Dales to the east, is perpendicular to the stream bed and the change in the landscape as one moves off the limestone and on to the Silurian rocks is quite dramatic. By site 10 the limestone has been replaced by the fine-grained mudstone of the Brathay Formation.
On completion of the Sedgwick Trail, our now very wet group went into Dent to see the Dent Marble tiles on the floor of the church and to get a hot drink before heading homeward.
The Geology of Carrock Fell Area: A Field Guide, Kabrna P. and Collins L.; C & PGS, 2015.
The Sedgwick Geological Trail.