284 YORKSHIRE NATURALISTS AT SEDBERGH. 



the distance where the Coniston Flags and Grits, by the great 

 Pennine faults, are thrown abruptly against the Mountain Limestone. 

 The descent was now made into Helm Gill, and by a precipitous 

 path the bed of the stream was reached. This is a most interesting 

 section, as here, by a fault running north and south, the Coniston 

 Limestone is exposed, this being the oldest formation seen during 

 the day. This limestone has from its fossils been correlated with 

 the Bala and Caradoc beds of Wales, which were included by 

 Prof. Sedgwick in the Upper Cambrian series. Murchison named 

 them Lower Silurian ; but Prof. Lapworth proposes to use the term 

 Ordovician, from the name of the British nation, Ordovices. This 

 fault separates the limestone from the shales and grits, but the former 

 dips rapidly to the south-west, and soon disappears ; in composition 

 it alternates between a very hard crystalline dark blue limestone and 

 crumbling shales. Careful search was made on both sides of the Gill 

 for fossils, with good results. Fragments of black mica trap were 

 seen here and there, and although not in situ, yet no doubt they had 

 been detached from the trap dikes in Helm Gill. Helm Gill is one 

 of the best places for a geologist we have yet seen. For the physical 

 geologist there is the remarkable fault already alluded to ; for 

 the palaeontologist the fossiliferous limestone and shales, with their 

 rich harvest ; and for the petrologist there is ample work in the 

 investigation of the trap dikes. The Gill was ascended, then the 

 path over the moors traversed, and crossing the Hawes and Sedbergh 

 road, Dovecote Gill was visited, to view a small cavern. In the 

 valley of the Rawthey some good exposures were noted of the Red 

 Conglomerate or basement bed of the Carboniferous series. This is 

 finely developed at and near Sedbergh, and consists of a mass of 

 pebbles enclosed in a ferruginous matrix. This conglomerate rests 

 unconformably on the inclined edges of the Coniston grits, and is 

 overlaid conformably by the Carboniferous Limestone series ; the 

 pebbles contained have been chiefly derived from the grits and slates 

 of the surrounding hills. For the origin and probable method of 

 formation of these conglomerates, the reader must be referred to the 

 account in 'West Yorkshire,' from the pen of Mr. Davis. The 

 inspection of these beds seemed to be, with several of the party, the 

 most interesting feature of the day's work. Return was now made to 

 Sedbergh for tea at the White Hart Hotel. No sectional meeting was 

 held, the return of the train being comparatively early. Amongst the 

 fossils obtained during the day were included Graptolites (several 

 species), Orthoceratites, Trilohites, Orthis, Sirophomena, Athyi-is, 

 Faiwsites, Haly sites, and some magnificent examples of E^icrinites 

 (one exhibiting both stem and tentacles). The richness of the district 

 made the day one of thorough enjoyment and practical benefit. 



Naturalist, 



