CONISTON LIMESTONE SERIES. 83 



preserved. Some of the best specimens have been obtained from 

 Keisley, north-east of Appleby, and here the Limestone, which is 

 better developed than at any other locality, is a white and pink 

 crystilline limestone. 



The Coniston Limestone stretches from Millom on the estuary 

 of the Duddon to near Ambleside and Wastdale Crag. It occurs 

 also in the Furness district, where the formation was called Ireleth 

 limestone by Sedgwick. It may be studied on the western side of 

 Troutbeck, in Westmoreland, in the valley of Long Sleddale, near 

 Kendal, and in Ravenstonedale. 



The formation is well exposed and highly fossiliferous in the 

 upper part of Helm Gill, and above Gawthorp near Dent, also 

 in Sarly Beck, north-east of Sedbergh in Yorkshire. Organic 

 remains have been obtained from a quarry by the road leading 

 from Coniston Waterhead to Ambleside, about two miles from 

 Coniston, and also at Sunny Brow, south-west of Ambleside.' 



Speaking of the Coniston Limestone, Mr. J. Bolton remarks that it is a hard, 

 compact, dark blue rock. It is not much used as a building-stone, being subject 

 to rapid decay by atmospheric influence, neither is it of much use for burning into 

 lime.* It burns to a dark-coloured lime, which has been used for agricultural 

 purposes and for cement. Hajniatite occurs in the Coniston Limestone of Millom. ■^ 



Ashg^ill Shales. 



This uppermost division of the Coniston Limestone Series was 

 so named by Sedgwick and Salter, from Ashgill, three miles south- 

 west of Coniston.* It consists of grey and green calcareous mud- 

 stones, sometimes affected by cleavage, with grey crystalline 

 limestone in the lower part. The beds attain a thickness of about 

 200 feet. 



Among the fossils are Trinucleiis concentricus, Phacops apictilafus 

 and P. miicronatus (two species which have been taken to mark 

 a zone), Orthis protensa, O. bi/orala, and Strophomena Siluriana. 



The beds have been traced from Coniston at intervals through 

 the southern part of the Lake District to the borders of Yorkshire. 

 Besides Ashgill, they may be seen at Rebecca Hill Quarry, north 

 of Dalton-in-Furness ; at Pull Beck, on the west side of Winder- 

 mere ; at Skelgill, and at Applethwaite Common, east of Troutbeck 

 in Westmoreland. Near Sedbergh the Trinucleiis and Strophomena 

 shales observed by Prof. Hughes, belong to this series ; and further 

 north he has traced them on the east of the river Lune, in Spengill 

 and Fairy Gill.*^ 



' See Sedgwick, Q. J. i. 444; Hughes, G. Mag. 1S67, p. 354; Harkness and 

 Nicholson, Q. J. xxi. 248, xxxiii. 467 ; J. E. Marr, Q. J. xxxiv. 872. 



^ Geological Fragments, p. 49. 



3 J. D. Kendall, Q. J. xxxii. 180. 



* Salter, Catalogue of Cambrian and Silurian Fossils, Cambridge, p. 72. 



^ Geol. Mag. 1867, p. 351 ; see also Harkness and Nicholson, Q. J. xxxiii. 469 ; 

 and J. E. Marr, Q. J. xxxiv. 873. 



